Horsepower opinion

[SourceLee]

Opinion please. What would you consider to be the ideal horsepower of a roadster? Sounds funny but here's where the question is coming from. Plenty of hot rodders say mild horsepower cars (mid 300hp) are more fun to drive than high horsepower street rods. The argument is high horsepower street rods always have the driver balancing the car. Hanging on the hairy edge of breaking the car loose and then losing control. Therefore the driver really can't "step into it"! Conversely mild horsepower cars can be "leaned on" with less worry of losing control. Heard an old quote: It's more fun driving a slow car fast rather than driving a fast car slow. I haven't had the pleasure (or displeasure) of driving a high horsepower lightweight car. I'm currently at 330hp with a smile on my face. Wondering if the smile would get any bigger with some additional horses. How much is too much?

[J R Jones]

As your profile states "FFR owner" and "read countless posts" you know about the chest beating and extraordinary numbers you will get in response. Then there will be displacement and current vs period correct.
You can have fun with 6 to 7 lbs per horsepower, but inevitably a situation will arise when whatever you have will not be enough. There will always be the latest Porsche or a kid on a crotch rocket. Lots of replies coming.
jim
Having slept on this topic, history and wisdom(?) comes to mind through an unlikely source. We were in our HS senior year and my buddy Tom's Dad bought him a 1966 Mustang coupe in bright red. It had the 289 four barrel and three speed manual. They negotiated four speed vs three and two barrel vs four barrel. We pondered altering the exhaust for a sound to impress onlookers (listeners?). It must have been Tom's father who weighed in, we were not that wise, but Tom concluded, "If I had glass packs I would just beat the car to hear the exhaust". I recognize that inclination in myself, cars and bikes.
Having road raced muscle cars, I know what highly stressed engines sound like. Loud exhaust on commodity production engines is flatulent and not impressive IMHO. I question the wisdom of extreme horsepower for the entertainment value of the sound, and Tom's Dad was right.

[GoDadGo]

I think 400 HP with 400 TQ is the sweet spot for these cars, but I can honestly say that I'm happy making 50-60 more than that.
It just took me a while to "Learn How To Drive The Car" so I'm happy having the extra power on demand.
The tough thing for me was to learn was how to roll on the throttle and ease into 2nd, 3rd, and 4th gears.
5th and 6th aren't an issue because "This Driver Gets Goosey" going anything past 125 MPH.

Hope This Helps & Anything Over 300 HP In My Mind Is Quite Sufficient!

Good Luck & Happy Motoring!

Steve
Dark Side MK-4 Roadster #8,515
https://www.factoryfive.com/whats-new/customer-steve-l-graduates-his-mk4-roadster/

[NAZ]

Horsepower is like money -- never enough. That said, you can have fun with a 36HP VW Bug. My 450HP Raptor is fun to drive but the V6 just sounds wrong and takes away from the experience. So what is it you want out of a new toy? Gonna race it? Just cruise it and look cool? Build it your way and don't fret about what engine or how much power. Any HP level on a pump gas car can be fun and reliable to drive or can be unpleasant -- depends on the builder's knowledge and skill level.

These HP posts make me chuckle. That skinny pedal on the right modulates the power and that thing between your ears controls it. If your 400, 500, 600 HP car just smokes the tires in every gear, the problem is not under the hood, it's in the rear of the car -- learn how to tune the suspension. I run around on the street with 800HP in my 2,500lb car and it's not a fire breathing monster that's hard to control. It starts right up and idles, but it's no soccer mom car -- it's loud and obnoxious and not very comfortable cuz it's literally a race car. When I stomp the loud pedal, there is no smoking tires and drama -- just lot's of exhaust noise and plants you in the seat.

But if I want to smoke the tires, it will.
162181

[zee]

Assuming it's a street car ...



It's more fun to drive a slow car fast than a fast car slow.

Your car is not slow. At all. That quote is for Miatas.


I'm currently at 330hp with a smile on my face.

Then you already know the answer. At 330hp, you're probably already traction limited than HP limited. I highly doubt you go fast enough to run out of horsepower.

BTW, horsepower is more useful to make you go fast (high speed). What you feel when you're accelerating is torque, not HP. HP comes at high RPM, so there's your another answer: do you find yourself running out of gear because you can't achieve a higher enough speed? I suspect the car isn't aerodynamic enough for that and you'll lift the car before you run out of HP.

As for the torque, that's another issue. Do you find yourself flooring the car and feel that you want it to move even quicker? Honestly, I doubt you're flooring the pedal.

So there you have it. I highly doubt you're using the entire torque and horsepower at your disposal, so what good is more going to do?

That said, I am not going to hate on people who want to hit a number to say their car has xx horsepower. Honestly, nothing wrong with that. If that's the goal, then go for it. But you're not going to enjoy driving more or likely drive any different.

[CaptB]

I think 400 HP with 400 TQ is the sweet spot for these cars, but I can honestly say that I'm happy making 50-60 more than that.


My thoughts exactly and where I'm planting my build at.

[CraigS]

It depends a lot on where you live. Especially w/ these cars, noise level may be more of a deterrent than actual HP. Full throttle in 2nd at 3000 may have you at just 45mph, but even w/ just 300hp, everyone within a pretty big radius will know what you are doing. I do agree that there is something about being at full throttle that is very satisfying vs needing to stay at <80 or 90%. I enjoy about 450 in mine. In the colder months I can't go 100% in 2nd or it will spin up the rears but then that is kind of fun too. I could run better tires but the $1700 every 1-1.5 years for my autocross Hoosiers keeps my street tires at the bottom end of the price range.

[edwardb]

This question has been asked a lot and 400 seems to be the number most often suggested. For a street driven car, properly set up, the right tires, etc. 400HP will give plenty of power and performance. For me anyway, what gets left out of these discussion many times is how well mannered that HP is. Depending on the cam, intake, induction, etc. whatever HP you have might be easily accessible. Or not. Sometimes higher performance engines don't like lower RPM's, for example. Makes them more challenging to launch and just pot around town if that's what you're trying to do. This factor alone is why I've really come to appreciate the Coyote in a couple builds. It's happy and makes great torque just about idle and up to whatever RPM you want. I'm amazed how easy and fun the cars are to drive when they run that way. The SBF's I had before (one mild, one pretty aggressive 347) while ran well were just not as fun to drive. Very much a personal opinion and not trying (again) to make a Coyote commercial. Just pointing out the discussion involves more than just raw HP.

[cob427sc]

Jumping on the wagon --- I've had roadsters from stock 302 through 475 HP and all were acceptable for what I was planning on driving at the time. I did build an early coupe, and since I was doing some consulting for Ford at the time, they built me and engine/tranny combo for the car. Their idea must have been that I was returning to Sebring for the 24 hour race as it was not a very streetable car. Cold start took 10 minutes to get close to idle, power came on above 3500rpm, etc. Car would fly when warm but just wasn't fun to drive. If I remember the dyno tag was 537HP with 450 torque. I ended up selling the car.

[NAZ]

The proper selection of cam, heads, intake manifold, and fuel metering device that all play nice together over a wide range will make for a high powered easy to live with engine. I often see guys select a cam, heads, and carb based on the highest possible flow rate that will fit under the hood and are never happy with the results. Big power can be made street friendly.

Or it can be a snotty, irritating, problem child if you select an incompatible combination of parts. Yes, I've done that too.

[Jim1855]

I have a 427w with about 540 crank and 440 wheel HP. Very drivable but doesn't like being under 1,800-2,000 rpm, did idle at 900 though. Would cruise at 80 all day long in 5th. .64OD, 3.27 315/35-17, this was in a previous car. Same motor will be going into the current build. Easy to cruise around town, worked in the mountains, started well but it had a Jeckel & Hyde personality. Treat it nice and easy and it responded with same, whack it and the story changed, rather quickly actually.
It's not so much how much you have but how you apply the skinny pedal.
Jim

[GTBradley]

I love my roadster and at 401hp to the wheels and nearly that in tq you just can't treat it the same as an MX5, which, by the way, is a little heavier. The thing is, you need to learn and use discipline when driving high hp / low weight cars and with lower hp cars you just don't. Discipline takes away from the fun just a bit and adds a technical aspect.

My favorite car to drive was the 71 Datsun 240Z, but my most satisfying is the Cobra. In the Datsun I could just experience the raw emotion without much thinking. With the roadster, when driving it hard, I'm constantly thinking about what limit I'm approaching without actually feeling it yet. And that, IMO, is the negative about the Cobra, the limits come on suddenly and seemingly without warning.

I guess it's like raising kids. Your child that is always pushing the limits and stressing you out. The one that needs constant instruction on how to stay out of trouble and is constantly breaking loose. Well, that one causes you to focus on stressful things too often. But it is very satisfying to see them, not only make it through, but use their skills to really come alive.

The child that brings home the A's and just knows how to stay out of trouble. The one that impresses you with their ability to perform without any drama. That one allows you to sit back and watch a little more. Rather than being in the pits with them fixing broken things.

You love both kids and feel proud of their abilities and eventual success, but for very different reasons.

I'd say if you like 5 pounds per hp you are probably more like the grandmother from Parenthood:

https://youtu.be/Z18vJwmxFFY

[Hoooper]

Im not sure what question is really being asked or if there is an answer, but the whole discussion hinges on so many variables it is impossible to compare experiences. Tires are probably the most important variable and are lots of the reason why you have builders who say they cant get traction until 3rd gear with their 400HP/400lbft but then also have setups like mine that get traction even nearly all through 1st when its warm out and always all of 2nd, with 600hp/500lbft. Then there's suspension setup, some just arent going to put down power as well as others and aside from there being a half dozen options for the type of suspension there are also numerous ways each different one could be set up to make it better or worse.

Going straight full throttle is a very short thrill in these cars, or most cars really, youre doing well over 100 within a handful of seconds from a stop. For me the real thrill and where the smile really shows up is in the twisties and thats where your big or small HP/TQ number really doesnt matter.

[Hellion]

I too am at 400+ HP like some others have posted, which IMHO is a nice "sweet spot" to be at for a 2,200 lb car. Rosie drives like a "normal" car as long as I (or my wife and adult children) drive her that way. Likewise, if we push the limits she'll respond accordingly and give us all quite a thrill. The key lies within what you want your car to be and what you put into her. Funny thing - Rosie had a supercharger when she was originally built. The original owner said he took it off because "it had too much power." Frankly, I've never said those words, nor would I say them in my lifetime. However, I have to assume that either he couldn't control his right foot, was not a "skilled" driver, or it a combination of the two. What came to mind were the immortal words of Clint Eastwood - "A man needs to know his limitations." Know yours, and you'll answer your own question.

[Papa]

I own three V8 vehicles and belive it or not, my FFR roadster has the least horsepower of the three. It also is the most likely to get me killed, but is the most exhilarating to drive. I'll add that at 438hp at the flywheel, it feels very manageable and has great street manners.

[ggunter]

You will get as many opinions here as there are days in the year on horsepower. My 347 from BPE dyno'd at 419 and 430 tq. It will break the tires and spin them in first and second gear just by mashing the gas. Third and forth hook up and your gone. In my opinion that is a pretty good horsepower for this car. But me being the horsepower junkie I am ordered a 427 just because I wanted one. A well tuned right foot is the key to how much power you can put down to the road. Probably a mistake but I can always go back to the 347 if I don't like it. I would think a well tuned 350 horsepower engine is the best combo for this car.

[Fman]

500+ HP Dart 427 w/Edelbrock PF4 EFI, 2500 miles on the car now. It is a blast to drive, not necessary to have that much horsepower but when the time is right sure is fun to hammer it when you want the power. The idle and sound of a stroker 427 is also very addicting along with some pride of badging your car a 427 :D I will give my local engine builder a well deserved plug here he built a very drivable engine at all RPM ranges could not be more pleased with how he set it up. And yes I can break the tires in third gear with no issues. As I have said before I drive the car with complete respect it is no joke and I realize it has way more HP than I have driving skills, I am very careful with my right foot.

That being said if your 330 HP puts a smile on your face would keep driving it and enjoying it.

[Jim Wehr]

350hp in my 306 powered MkII. It's plenty enough to kill me anytime I'm feeling like doing something stupid.

[NAZ]

For those that don't fly, back in the day, the Piper Cub was the premier trainer that was easy and cheap to fly and only had 85 HP. It can just barely get out of it's own way.

There's an old pilot proverb that says the Cub is the safest airplane ever made. It has just enough horsepower to kill you. The reality is, any car can kill you if you don't respect it. Doesn't matter how much horsepower is under the hood. Be safe out there.

[facultyofmusic]

I'll probably get laughed at for doing this, but I fully intend to either remap my throttle pedal or use a physical bump stop to prevent me from being able to press the pedal more than 50% within the first few months of driving my 460HP coyote roadster. The road has no room or tolerance for shenanigans and the last thing I want to do is accidentally get myself and another innocent soul killed.

[Blitzboy54]

I have 375 (380 torque) at the crank and so far it is my sweet spot. I also tracked motorcycles and did some of my best times on lower powered lighter bikes. My build kept that in mind. Keeping RPMs high and installing massive brakes was my recipe for success.

[NiceGuyEddie]

Having had two motors in the same car, my personal experience is horsepower makes a tremendous difference in acceleration from say 60-120mph. You can throw my car in 4th even at 70mph on the freeway and it keeps you back in the seat all the way up to redline.

0-60 times will depend more on your tires, and will differ little for any V8 in a Cobra.

[Fman]

I'll probably get laughed at for doing this, but I fully intend to either remap my throttle pedal or use a physical bump stop to prevent me from being able to press the pedal more than 50% within the first few months of driving my 460HP coyote roadster. The road has no room or tolerance for shenanigans and the last thing I want to do is accidentally get myself and another innocent soul killed.

FWIW it took me a few months to start to actually feel comfortable driving the car. Being so low to the ground is a very different feeling than I had ever experienced before. I really drive mine how I used to ride a street motorcycle, full defensive mode assuming everyone is just going to hit me and people can't see you.

[Hellion]

FWIW it took me a few months to start to actually feel comfortable driving the car. Being so low to the ground is a very different feeling than I had ever experienced before. I really drive mine how I used to ride a street motorcycle, full defensive mode assuming everyone is just going to hit me and people can't see you.

As with any new relationship, you generally take it slow and easy at first...but as soon as you get to know each other a little bit better...you start hammering away - HA! :p

[TBull]

We've all read so many of these posts and I truly feel there isn't a wrong answer. It's more of a very personal choice. Many people can say that is too much or not enough. They can be awesome builders, but in the end it is their opinion and it may influence your choice but it is your choice.

I drove my MKII at around 450 rwhp for ten years. I knew just how she would respond in many different situations, but I was at the limit for the engine. I drifted in corners if I wanted, but it could be very mild mannered. There were some times when I was pushing it and I just needed more speed. On my new build I made the choice to go higher with the horsepower. I fully intend to track the car and do autocross along with cruises. I'll get to know the new one as well over time but in the end I wanted to push the car harder.

In my opinion it's all up to you and what you want to do with your car. Take the input or don't, but once you make your choice, then stick with it and don't listen to anyone that wants to say you should have done it differently.

[facultyofmusic]

I do think, though, that even if you don't want that much power for the street, being able to go to an autocross coarse and just let it rip is a glorious thing. BECOME THE TRACTION AND STABILITY CONTROL.

[AROCK]

I do think, though, that even if you don't want that much power for the street, being able to go to an autocross coarse and just let it rip is a glorious thing. BECOME THE TRACTION AND STABILITY CONTROL.

I race a 2600lbs drag truck for years with 1400 hp. With no problems controlling traction and hp.
In 1981 I build a contemporary cobra with a Homer & Moody Tunnel port with dual Nascar 660 carberators, top loader trans,and a Jag reverend. The car would light up the tires in 4th gear. It would literally burn the tires off the trims and I loved every minute driving the car.
I just finished building a 427 stroker for my present build and the hp should be around 650, with 600 ftp of tq. The combination is what I wanted to drive.
A friend of mine had an original SC 427 in 66. He owned a Lincoln Mercury deal ship at 21 years of age and we drove the hell out of that Cobra blowing the engine twice. So I am well aware of the limitations of the cars.
The FF kit is is a Porsche compared to the original cars. The original cars would be a covered wagon compared to Porsche.
The FF will handle all the HP you throw at it as long as the driver has the skill to handle the car.

[J R Jones]

Mark Donoghue did the development testing of the Porsche 917/30 Can Am car while driving the Weissach engineers nuts. He was asking for more power at 1100hp. "What is enough power"? they asked. Donoghue said "When I can spin the tires down the straight in top gear." Mark was exceedingly talented at using that power but the car did become airborne on a couple of occasions. I venture that there is not Mark Donoghue talent on this forum, and forum cars are not raced like Can Am cars. Indeed the primary exhibition of speed is pulling a couple of gears in a straight line.

My preference is balance and proportion that instills confidence in the car and the driver's skill, "We can do almost anything together". I have driven three cars like that, well four.
One was a live axle rotary with worm/sector steering and 11.5 lb/hp. My first extraordinary experience was a drift through a corner when a deer popped out of the ditch. No drama, lift, steer, avoid.
The second was a mid engine turbo with upgraded suspension. There was seemingly nothing that would upset it at 10.4 lb/hp. It instilled total confidence.
The third was a 500hp twin turbo V6 front, transaxle rear, at 7.6 lb/hp and lots of OEM nannies. At that performance level it was stable but alarming.
Acceleration g-force is fun, but there is a lot to be said for balance and confident control.
SourceLee, you did not ask "How much power can I handle?" or "How much power can my home-built handle?"
jim

[SourceLee]

Jim.
How much horsepower can I handle? I haven’t the slightest clue. This is the reason why I was looking for a little guidance. Didn’t want to get myself into trouble or make the car unenjoyable. Hey, check this out…. I wanted an answer to a question but I received something better. An understanding. This forum presented some hard questions which illuminated the real desires. Now that I have a clear target there’s a better chance I’ll hit it. All kidding aside, everyone’s comments were helpful and really appreciated. Thanks

[GoDadGo]

Jim.
How much horsepower can I handle? I haven’t the slightest clue. This is the reason why I was looking for a little guidance. Didn’t want to get myself into trouble or make the car unenjoyable. Hey, check this out…. I wanted an answer to a question but I received something better. An understanding. This forum presented some hard questions which illuminated the real desires. Now that I have a clear target there’s a better chance I’ll hit it. All kidding aside, everyone’s comments were helpful and really appreciated. Thanks

Should you find yourself near New Orleans, I can arrange for rides in the following:

> 33HR 400 SBC BPE / 4-Link
> MK-4 396 FE Big Block / IRS
> TP65 392 SBF Windsor / 3-Link
> MK-4 383 SBC Dart / 3-Link
> MK-4 351 SBF Windsor / 3-Link

All of my F5 Pals are happy to take new F5 Family Members for rides.

Good Luck & Watch Your Pinkies!

[SourceLee]

You’re a good person GoDadGo. Thanks!

[BEAR-AvHistory]

Think its all about what you want to do with it. I wanted a quick car with low maintenance. Light AutoX & occasional track days. Maybe a few runs in Mexico but mostly a car I could drive everyday I felt like taking in out.

Slightly modified & tuned for 93 octane Coyote, true power unknown, will run down the street in the sub division at idle in 1st gear with no shakes or stutters low noise to keep the neighbors happy. In a reasonably hard sub 2000 rpm launch for me its throttle/clutch management to maintain traction.

Usually successful sometimes not. Have not been able to do a Dragy yet weather is too cold since I got new tires NITTO NT-01 in 315 & a fresh clutch. Prior timings showed a 3.2 to 60 with NITTO 555R in 315.

My M4C 4,000lbs rated 503BHP not even bothering with launch control can just slap the pedal to the floor & the computer does the work for a Dragy 3.07 to 60mph. Point is I believe king of the street days with big power in an all manual car are over. The COBRA will be very quick but there are a number of cars with power & nannies that would be hard to match. The M4C was only #10 in MT's quickest cars tested in 2021.

My choice to recommend to anyone is get a Coyote. Install it & outside of oil, coolant & filter changes forget about it for 100,000 miles. Car will very quick & start anytime you turn that little key.

[chuckster]

With 386 at the crank, 330 at the wheels (]which is what I’ve got) thes cars are very close to what the original 289 FIA/USRRC were pushing back in the day. And these FFRs are much better mannered.

[Alan_C]

This question is often answered more with what someone wants vs. what they need. We don't need more that 300 RWHP in these cars, but we want more. As mentioned torque is what accelerates the cars, but it is torque that also wants to spin the tires and bring the rear end around. So it is a balancing act to get a quick, fast, and yet well mannered car. IMO that is where the Coyote shines, with about 400 RWHP and similar torque, perfect for pulling a 2300 lb. missile around. So my suggestion would be 400 squared, rear wheel torque and HP. Unless you are racing you don't need any more to have a lot of fun.

[nucjd19]

I have really enjoyed reading everyone's response on the question. Most of us asked ourselves a similar question when we started down this path. There are a few folks on here that knew exactly what they wanted right out of the box. I went through the usual process of power, price, HP, Torq, looks, reliability and cost. This is so personal for everyone. Sort of like what is your favorite song. for me it broke down like this performance ( wanted around 400hp) then looks ( I really like the SBF and FE looks), then cost ( had a range I wanted to hit) then finally it was reliability ( This is a weekend fun car with most miles being riding around the foot hills of the Appalachian mountains with rare auto cross/ track days ). There are no wrong answers. My experience? my sweet spot was the 347 Stroker from BPE. 415 HP and 420 ft-lbs torque. Maxing out the SBF (which is a little lighter but does not give me any wiggle room for squeezing out much more power down the road without risking the block). I went with a carb as well due to my preference for carb rigs and not living at altitude. I really like the look and sound of the SBF and the FE engines and was not a fan of the coyote looks although a superior everyday engine regarding reliability and plug and play. But that is what I wanted. Am I happy?????? I can say unequivocally......yes!!!! My engine is a Torque monster but I have the throttle linkage set mild to moderate and the throttle response is not binary allowing for a really enjoyable cruising experience but a quick reminder of what is under the hood with a blip of the throttle. Do I have regrets??????...... Maybe............. The 427 is so iconic in these rigs and it would allow more of an envelope of performance mods since the block is not at the maximum. But again my roadster is not a replica by any means and the performance envelope of my rig at this point is far beyond my ability to pilot it. Maybe my next build will have a 427 ;) Good luck :)

[Ford & Jeep Fan]

Having had two motors in the same car, my personal experience is horsepower makes a tremendous difference in acceleration from say 60-120mph. You can throw my car in 4th even at 70mph on the freeway and it keeps you back in the seat all the way up to redline.

0-60 times will depend more on your tires, and will differ little for any V8 in a Cobra.

This /\ /\ /\

[NAZ]

162285

[SourceLee]

I have really enjoyed reading everyone's response on the question. Most of us asked ourselves a similar question when we started down this path. There are a few folks on here that knew exactly what they wanted right out of the box. I went through the usual process of power, price, HP, Torq, looks, reliability and cost. This is so personal for everyone. Sort of like what is your favorite song. for me it broke down like this performance ( wanted around 400hp) then looks ( I really like the SBF and FE looks), then cost ( had a range I wanted to hit) then finally it was reliability ( This is a weekend fun car with most miles being riding around the foot hills of the Appalachian mountains with rare auto cross/ track days ). There are no wrong answers. My experience? my sweet spot was the 347 Stroker from BPE. 415 HP and 420 ft-lbs torque. Maxing out the SBF (which is a little lighter but does not give me any wiggle room for squeezing out much more power down the road without risking the block). I went with a carb as well due to my preference for carb rigs and not living at altitude. I really like the look and sound of the SBF and the FE engines and was not a fan of the coyote looks although a superior everyday engine regarding reliability and plug and play. But that is what I wanted. Am I happy?????? I can say unequivocally......yes!!!! My engine is a Torque monster but I have the throttle linkage set mild to moderate and the throttle response is not binary allowing for a really enjoyable cruising experience but a quick reminder of what is under the hood with a blip of the throttle. Do I have regrets??????...... Maybe............. The 427 is so iconic in these rigs and it would allow more of an envelope of performance mods since the block is not at the maximum. But again my roadster is not a replica by any means and the performance envelope of my rig at this point is far beyond my ability to pilot it. Maybe my next build will have a 427 ;) Good luck :)

These are the hard questions I was referring to. Well put

[GoDadGo]

Power To Weight Ratio Is Definitely Where It's At With These Cars!

Then comes the gearing and that's what sends power to the rubber where it meets the road.

Engine Torque..X..Trans Gear Ratio..X..Rear Gear Ratio..=..Total Torque Output (Minus) Internal Friction Loss

The cool thing for me is my Porsche Pals all compare their cars to mine, yet the technology and design they are comparing their cars to was developed nearly 60 years ago, 57 to be exact if you are making that comparison to the 427 Shelby Cobra...For my dream car I tried to split the difference between the Rev-Happy 289 and that Infamous 427 with 383 cubes... For the record, 358 cubic inches is the dead center displacement target between those two famous cars so all I can say is:

Built Not Bought!
Torque Matters!
Wrench Drop!

[JohnnyB]

Having had two motors in the same car, my personal experience is horsepower makes a tremendous difference in acceleration from say 60-120mph. You can throw my car in 4th even at 70mph on the freeway and it keeps you back in the seat all the way up to redline.

0-60 times will depend more on your tires, and will differ little for any V8 in a Cobra.


This /\ /\ /\

Interesting, I don't think I've ever seen the comparison put this way. I guess that explains why I've been happy with my paltry 225HP donor engine for all these years. When I built the car I fully intended to upgrade the engine at some point with a supercharger or better heads. For the type of driving I do I still haven’t seen the need. I won’t dispute that more is better to a point but I can attest that these cars are still plenty quick and an absolute blast to drive with lower horsepower engines.

[Dave Tabor]

Here is a a side-by-side comparison at the drag strip:

https://youtu.be/NayXVsBNkbw

Left lane: me with 345hp FRPP 302 crate motor (13-second car).
Right lane: buddy Jeff with 500hp FRPP crate motor (11.5-second car).

Same trans and gearing.

Once I hit 3rd, he's gone.

Dave
Gen III Coupe #17

[GoDadGo]

Dave,

What R.E. Gears Are You Guys Running?

Steve

[Dave Tabor]

Dave,

What R.E. Gears Are You Guys Running?

Steve

Same at 3.55.

Dave

[j.miller]

Ok, Don't laugh. I have driven from180hp to 650hp. My car had 300 and I liked it just fine for my purpose. Over 400hp "non coyote" the car starts driving you. If I had to do it again I would(and almost did) go would go with a warmed over 289 with 180 hp and a RV cam. There will always be someone faster but you could really work that 180hp car with gas, break and clutch all at the same time.....I liked it because it did what I wanted it to do with very few surprises. jus sayin...da Bat

[GoDadGo]

Over 400hp "non coyote" the car starts driving you.

Yep!

I'm always a tad tense when Mrs. Go-Dad and I go out cruising.

[chmhasy]

Yep!

I'm always a tad tense when Mrs. Go-Dad and I go out cruising.

Isn't the dark side like negative horse power, LOL

[nucjd19]

Isn't the dark side like negative horse power, LOL

No it is antimatter and when matter and antimatter collide you have complete annihilation of mass and release of a massive amount of energy......hence GoDad's concerns when he pulls it out of the garage :)

[rich grsc]

Isn't the dark side like negative horse power, LOL
I think it equals .6427 Ford hp.:rolleyes:

[GoDadGo]

Isn't the dark side like negative horse power, LOL

Yes, there is a Negative Side to Dark Side Power.
It seems you only need 383 Cubes to keep up larger power plants from other manufacturers.

[TriPower]

I started at 350 hp for 2 years and it became fun but not as much as I wanted. I replaced engine with 347 ci making 490 hp at the crank. I would not go over 500 hp, IMO. What helps control the car is my 5 link and torsen diff. My mechanic loves my car he can get on it and it goes straight. He also works on an ERA with full independent suspension. When he gets on it, it is all over the road and he must be very careful.

HP is one thing, control is another. Also, sticky tires. I use Nitto NT05 and street and road events. Note I have 54000 miles on car with over 6000 miles on track days. I love Road America and have hit 145 mph but not often.

Lee

[NAZ]

Yes, there is a Negative Side to Dark Side Power.
It seems you only need 383 Cubes to keep up larger power plants from other manufacturers.

That a boy Steve!

I don't feel at a disadvantage with my my dark side SBC compatible power, it makes more than any Ford I've had. And a 1.97HP per CI, not bad for a street car with no power adders.

[GoDadGo]

427-CID / 3.23 GR Backdraft / I.R.S. / Mr. Scott
383-CID / 3.73 GR F-5 MK-4 / 3-Link / Go-Dad
351-CID / 3.55 GR F-5 MK-4 / 3-Link / Heath

My friend Heath and I attended a Hot Rod Run where we met a fellow with a 427 Powered Backdraft.
We had three different engine sizes, power levels along with three different rear gearing ratios.
When we left we decided it was time to go play with the cars to see how they stacked up.
My big takeaway was that they were all evenly matched in spite of power output levels.
Wheel spin was a problem we all had; however, Heath seemed to deal with it the best.

[WBILB]

162285

A wise man once said that "the only reason to have 1000 HP street car is so you can say you have a 1000 HP street car.

[RFracer]

427-CID / 3.23 GR Backdraft / I.R.S. / Mr. Scott
383-CID / 3.73 GR F-5 MK-4 / 3-Link / Go-Dad
351-CID / 3.55 GR F-5 MK-4 / 3-Link / Heath

My friend Heath and I attended a Hot Rod Run where we met a fellow with a 427 Powered Backdraft.
We had three different engine sizes, power levels along with three different rear gearing ratios.
When we left we decided it was time to go play with the cars to see how they stacked up.
My big takeaway was that they were all evenly matched in spite of power output levels.
Wheel spin was a problem we all had; however, Heath seemed to deal with it the best.

My FIA ERA has a 331 SBF with a jag irs 3.31. Power feels similar to previous FFR Roadster w 3.73 3 link rear mated to a 302 380ish hp and FFR coupe with 3.55 irs with a 351 410hp. My first was a donor roadster 302 215hp with stock 4 link 8.8 3.27 gear I think?The first was a full donor build slug compared to the next 3. The ERA has webers making it very snappy. Honestly can’t see a need for more than 425 crank HP with a 2,200# car.
Rich

[Alan_C]

Matter to matter collisions are pretty devastating too. Saul from the San Diego area only had his supercharged Coyote powered MK4 on the road for a few years before a collision with a tree brought the car to a rest. I would guesstimate his HP at around 800 HP, just too much to be safe (obviously).

[NAZ]

800 HP is unsafe? Really? So, how much HP is safe? Is it 700? 500? 400? And what makes that level safe?

163665

[Windsor]

"Too much to be safe"... for that particular driver. :)

[Namrups]

IMO debating the safety of HP values is a silly discussion. These are not self driving cars. The HP is controlled by the driver behind the wheel. There are folks that can drive a 600HP car very safely and there are people that can't drive a 200HP car safely. The drivers right foot is what make the car safe or not.

[NAZ]

There are many mechanical items that can impact safety but horsepower is not one of them. The designer, the builder and the maintainer can all influence safety but the operator has the most control over safety. For every mechanical safety issue, an exhaustive root cause analysis will lead back to a human failure. Stating that some arbitrary level of HP renders a vehicle unsafe is a myopic view and stating that as an absolute is simply wrong.


Yes, it would be foolish to hand the keys to an 839HP Dodge Demon to a newly minted 16-year-old with limited experience and even less self-control but that doesn’t mean that car is unsafe. And the same could be said for some drivers considerably older than 16.


It’s not the HP that makes a vehicle unsafe – it’s a human. And that’s usually the one at the controls.

[Jeff Kleiner]

It’s not the HP that makes a vehicle unsafe – it’s a human.

I've heard a wise man (Bob Cowan ;)) say on more than one occasion "There's no such thing as too much power, only not enough control."

While instructing I've reminded many students that the pedal on the right is like a hinge and goes both ways---down AND up!

Jeff

[J R Jones]

I have been referred to as stupid here, for describing physics. I assumed name calling to be improper forum behavior if not poor taste. That notwithstanding:

Driving enthusiastically could be described as two dimensional flying. A car substitutes the coefficient of friction for lift.
You are allocated and constrained by weight and square inches of tire contact patch(es) to result in PSI (pounds per square inch) at each corner.
This is not what you see on your weight scales because it is a dynamic, always shifting fore/aft and side to side. One tire gets more when another gets less.
The road surface is not static either. It gets dusty/dirty and wet or frozen throwing out the value of your PSi. Living in the frozen North requires skill adapting to PSI impairment.

Brakes use all the sq inches, while the throttle goes through one or two patches.
Yaw uses all the contact PSI but often has to share with acceleration or deceleration or excess steering angle.
A frustrating reality is that too much force causes the contact patch(es) to feel like they are lubricated. Once broken by acceleration or deceleration or angle, the contact patches have to be brought back to near zero differentiation of relative surface speed or angle to recover.

A large number of enthusiastic drivers do not have a notion of any of this. They drive for the exhaust noise and the thrill of G-forces.
The danger of those drivers to themselves and others is proportional to the force they can apply. Yes, engine power, especially disproportionate power, can overwhelm the unskilled or unenlightened.
jim (emoji free post)

[BEAR-AvHistory]

Ok, Don't laugh. I have driven from180hp to 650hp. My car had 300 and I liked it just fine for my purpose. Over 400hp "non coyote" the car starts driving you. If I had to do it again I would(and almost did) go would go with a warmed over 289 with 180 hp and a RV cam. There will always be someone faster but you could really work that 180hp car with gas, break and clutch all at the same time.....I liked it because it did what I wanted it to do with very few surprises. jus sayin...da Bat

I run a coyote & wonder if you could explain a little more of the why they might be OK at 400+.


GoDadGo

Dave,

What R.E. Gears Are You Guys Running?

Steve

3:55

Back in the day most of my cars were 3:55 or 3:70. Seemed like good all round gears that you could run every day & still go to the drag strip on the weekend

[Jim1855]

I run a coyote & wonder if you could explain a little more of the why they might be OK at 400+.

I think one advantage of the Coyote is that it's well refined and doesn't exhibit the temperamental behavior of a higher HP carb'd motor. The EFI system keeps the motor in check. This isn't to say that a carb'd motor can't or won't run smoothly, mine seemed to but still had it's own attitude. Many others do as well but then there are those that aren't so well behaved. I believe that Naz has mentioned the complicated combinations of parts, some selections working well together or better than others.

I was considering EFI to replace the carb on my 427w. My tuning friend offered that he could tune out the rough spots that are difficult to remedy with a carb. The control pack with the Coyote does this, or as mentioned by other members in other posts, will with the proper tuning. EFI is, in many ways, similar to the fly-by-wire systems in some or many planes, making the difficult to fly easier.

Now something about HP/TQE. Pretty much any motor will move a roadster. 0-60 is pretty snappy, 60-120 changes things, aerodynamic drag causes problems. I can tell you that a good 351w can't hold a candle to a 427w or a 500 c.i 385 series from 125-150 and even then the 427w gets a bit sluggish after 140. Pushing a roadster at speed is about the same as moving a greyhound bus.

Make your decisions, choose your poison.

Jim

[toadster]

IMHO knowing how to drive >>>>> HP at the wheels

we've had a few Miata's in our history, and let me tell you - even though many think they're underpowered cars, they can get around corners very quickly if driven well - they can drive "faster" than many 500 HP cars that are traction limited, good in the straights only, or just is too much power for a small car

sure 400-500HP sounds great, but can you keep all 4 on the ground? :rolleyes:

[NAZ]

sure 400-500HP sounds great, but can you keep all 4 on the ground? :rolleyes:

I can, and do but I realize that many have problems getting moderate power to hook. And this is why there are so many opinions about how much power is practical or usable. Some can crack the code on traction and some haven't figured it out yet -- but anyone can if they are resourceful and study the subject.

But then it doesn't take a bunch of power to have fun. I have a blast with my drag car and 1,100 HP on tap but I also love driving my SXS with 230 HP as it will travel 3' whoops at 80 MPH and that can be exciting. But some of us will always be wanting more power, climb steeper hills, catch more air over jumps, and fly higher. It's just in our nature. But I can also have fun on a 6 HP mini bike racing my buddies up and down my 1/4-mile driveway.

When it comes to power, my advice is to get as much as you can afford and use the skinny pedal to control it. No matter how much we have, some of us will outgrow it in time. Learn how to get your car to hook, turn, and brake and that will up the fun factor no matter how much power you have.

[NiceGuyEddie]

Here is a a side-by-side comparison at the drag strip:

https://youtu.be/NayXVsBNkbw

Left lane: me with 345hp FRPP 302 crate motor (13-second car).
Right lane: buddy Jeff with 500hp FRPP crate motor (11.5-second car).

Same trans and gearing.

Once I hit 3rd, he's gone.

Dave
Gen III Coupe #17


This is EXACTLY what I meant in my post #22 when I said:

Having had two motors in the same car, my personal experience is horsepower makes a tremendous difference in acceleration from say 60-120mph. You can throw my car in 4th even at 70mph on the freeway and it keeps you back in the seat all the way up to redline.

0-60 times will depend more on your tires, and will differ little for any V8 in a Cobra.



I did some HARD driving yesterday and even after 15 years of ownership I said to myself, "I can't imagine this car being any faster." But then, I was 80mph and below.

[J R Jones]

I can, and do but I realize that many have problems getting moderate power to hook. And this is why there are so many opinions about how much power is practical or usable. Some can crack the code on traction and some haven't figured it out yet -- but anyone can if they are resourceful and study the subject.

But then it doesn't take a bunch of power to have fun. I have a blast with my drag car and 1,100 HP on tap but I also love driving my SXS with 230 HP as it will travel 3' whoops at 80 MPH and that can be exciting. But some of us will always be wanting more power, climb steeper hills, catch more air over jumps, and fly higher. It's just in our nature. But I can also have fun on a 6 HP mini bike racing my buddies up and down my 1/4-mile driveway.

When it comes to power, my advice is to get as much as you can afford and use the skinny pedal to control it. No matter how much we have, some of us will outgrow it in time. Learn how to get your car to hook, turn, and brake and that will up the fun factor no matter how much power you have.

Going a bit deeper here. When you are one with the car, you will feel the tire contact patches.
You will also sense the harmony of function, when the parts and the assembly perform properly.
This leads to control without stress and prolonging the life of the parts. However, expectations and time frame drive alternative outcome.
If your performance expectation is 100% for 1/4 mile <10 seconds or 25 laps, expect consumption and perhaps consequence.
There are also consequences to exercising 100% on the street, moreso at mega thresholds.
jim

[BEAR-AvHistory]

I think one advantage of the Coyote is that it's well refined and doesn't exhibit the temperamental behavior of a higher HP carb'd motor. The EFI system keeps the motor in check. This isn't to say that a carb'd motor can't or won't run smoothly, mine seemed to but still had it's own attitude. Many others do as well but then there are those that aren't so well behaved. I believe that Naz has mentioned the complicated combinations of parts, some selections working well together or better than others.

Jim

Thanks for the reply. Felt the same way just wanted to know what others thought. I knocked a bit of bottom end torque out of the engine with a BOSS-302 intake. Is easier to launch & added a bit of bling the regular manifolds that are more efficient don't have. With 315 NT01 it will still compress your eyeballs.

[Ford & Jeep Fan]

800 HP is unsafe? Really? So, how much HP is safe? Is it 700? 500? 400? And what makes that level safe?

163665

Chrysler has some new software that has the new Hellcats limited to 2.8HP (That decimal point is CORRECT!!) https://www.roadandtrack.com/news/a35926169/dodge-charger-challenger-security-mode/?utm_medium=social-media&utm_source=twitter&utm_campaign=socialflowTWRAT&src=socialflowTW