I want a 351W. What am I in for?

[Mugzilla]

If I am building a FFR Mk4 roadster, I am going to do something "greater than moderate" with the engine. I've had fox body mustangs with the 302, and they were fun. I can't wrap my head around the 347 and the way you have to relieve the block, and the way the bottom ring protrudes when the piston is down.

I want a 351W.

Can anyone make any recommendations? Things to look out for? Blocks to look out for? Reputable engine builders for a short block?

[CFranks]

I have a Ford racing 427 based on a 351 Boss block, came from Mike Forte who I’m sure you’ll see will be recommended very highly on this forum. As to what you’re in for.... it’s awesome, sounds great, looks great, runs great, awesome low end torque. Just be prepared for horrendous gas mileage if you stroke it (if that matters to you).

[Gordon Levy]

351 base is a nice package. Stage 4 version from me is a solid 450hp. The strokers are as much as 610hp on pump gas and can be driven daily. Really depends on what you want out of your car.

[KDubU]

The 351w is a great engine and either Mike Forte or Gordon Levy can build you one that you will enjoy. I went with it over the 347 as I thought I may want to stroke it later on plus the $ diff was minor. A 347 is great in the these cars as well as long as you have a good builder.

[Mugzilla]

I am researching a non-stroked 351W. I am not a fan of assembling the lower end; I don't need to "refresh" my marginal experience on an engine that I expect performance out of. Heads, intake, and accessories are fine. I believe I still have a set of AFR185 heads in the shed.

[Sdonnel]

I just recently finished a build with a 351W. I used the AFR185 heads and forged internals. Engine is internally balanced and with a nice Isky cam, the Fitech just sits on top and screams when I want it to and putters along the rest of the time. My mileage on the highway is 18 MPG. I'm not worried about mileage with this car, but I have to say I was surprised on my first road trip. The longer I drove, the better the Fitech ran. I'm at 10.5:1 compression and right at the limit on pump gas, so keep that in mind. Too high of compression and you will have to source race fuel to support your habit. The torque on a 351 based motor "feels" like it comes on sooner than my old 302 based motor (with AFR heads). That's measured at the base of my spine when I smack the loud pedal. As stated above. Talk to the forum vendors and tell them what you want. You will not be disappointed.

Scott

[edwardb]

A 351 block is a good choice. Many on here will support and recommend. Just watch the height on the intake, carb, air cleaner, etc. Easy to run out of height there and be against the hood due to the increased deck height of the 351 block.

Also, just for the record, the comments you made about the 347 aren't the case if done properly. Relieving the block isn't a big deal, unless you use an aftermarket block like I did. Which is now routinely recommended anyway. Also, with the right pistons and block the rings aren't coming out the bottom of the bore. A 347 is also a good choice and a proven setup. Just saying.

[FF33rod]

You asked about a short block. Check Levy and Forte as mentioned. I used TRE Performance for a 347 short block, top end kit ,... also Blueprint is a great way to go, they are extremely helpful and know what fits in the various FFR kits
Steve

[JRL16]

I used an Engine Factory 351w based 427w. Nice power and sound. As Edwardb states you can run into issues with under hood clearance. Not a problem if you're using a hood scoop. One caution I have is the oil pan. I have seen some builds, not always FFR's at car shows where the engine builder used a pan that hung below the cross member. Not a good idea. Other than that they have an unmistakable rumble, fit nice and neat, and have ample power. Good luck.

[Jeff Kleiner]

...Just watch the height on the intake, carb, air cleaner, etc. Easy to run out of height there and be against the hood due to the increased deck height of the 351 block...



Agreed. Stay away from the Performer Air Gap intakes or others of the same height and hood to air filter clearance will be OK.

Jeff

[mike223]

I'm at 10.5:1 compression and right at the limit on pump gas, so keep that in mind. Too high of compression and you will have to source race fuel to support your habit.



GoDadGo and I both stroked 350/351 engines (to 383/393) and went with ~10.5:1 compression.

We've decided if we ever have to build them again we'll stay at 350/351 displacement and a lot more like 9:1 compression.

That's for 200TW street tire / street car use - we've concluded we would be just as happy with a little less HP/TQ and run it on regular gas too (bonus).


It's literally a question of how fast do you want to be going in third gear and still spin the tires at will? (it sounds like more fun than it actually is)

[GoDadGo]

GoDadGo and I both stroked 350/351 engines (to 383/393) and went with ~10.5:1 compression.

We've decided if we ever have to build them again we'll stay at 350/351 displacement and a lot more like 9:1 compression.

That's for 200TW street tire / street car use - we've concluded we would be just as happy with a little less HP/TQ and run it on regular gas too (bonus).


It's literally a question of how fast do you want to be going in third gear and still spin the tires at will? (it sounds like more fun than it actually is)

Amen Brother Mike, Amen!

https://youtu.be/CaRlqMmKIzk

I scared myself the other day when wheel spin occured in 4th gear because it was a little cool (65 F) on that day.

[Boydster]

I have a 351/427 with an Air Gap intake and an FiTech. Had to go to an 8x1.5" filter (no-drop lower because of the fuel fittings) with a filtered lid to stay inside and under the scoop. With a wingnut, had 1/4" clearance to the inside of the scoop. Changed to a bolt and now have about 1/2".

However, plenty of clearance around the sides to do whatever (plugs, header bolts, etc).

Just be careful what combo you choose with a 351.

[mike223]

Amen Brother Mike, Amen!

I scared myself the other day when wheel spin occured in 4th gear because it was a little cool (65 F) on that day.




Yeah, that's another part of the (same) question - Do you really want to wag the tail in 4th gear?

Careful what you wish for...

[GoDadGo]

Yeah, that's another part of the (same) question - Do you really want to wag the tail in 4th gear?

Careful what you wish for...

No, I Didn't Expect The Snake To Strike!

I snuck out to make an less than legal drive on the highway the day that LSU played Al-Er-Bam-Er.
I figured no Purple & Gold Bleeding Louisianian would be on the roads and they weren't so I let her rip.
At 3,500 RPM's 4th gear got interesting and Thank God I still have the rev limiter set at 4,300 so it settled quickly.
Though I'm only making around 450 HP with similar torque figures, the 3.73 ring and pinion makes every gear shift interesting.

3500 RPM + 4th Gear = 72 MPH
4300 RPM + 4th Gear = 89 MPH

[canuck1]

I built my own 351w (stroker). I like it, but if I was starting from scratch, I'd opt for a 5.0l/302 based engine rather than the taller, wider 351w type.

I like the horsepower, but you can easily get plentiful hp from a 347. The boatloads of torque that come with a longer stroke just isn't required in a light car like this, imho. I have often considered the 331 or 347 stroker as a better setup. Everything that's available aftermarket is made for the 5.0l based engines. It's not that they don't make distributors, induction systems or headers for 351w engines, there's just a lot fewer out there, so you often need to be prepared to pay a little more and sometimes wait a little longer. I have a MKIII chassis that was built to fit the girth of a mod motor, but I still can't get my hand in far enough to pull the plug wire on #8. I need to do it from underneath. I still had to form some extra clearance on the driver's side to keep my header tubes off the aluminum. There are real limitations on air cleaner clearance you can work around, but these aren't an issue with the shorter 5.0l engine. Some people claim 70-74 351w blocks are a heavier casting (more durable), but roller lifter capability didn't arrive for the 351w until 94. That's another workaround you won't need to figure out if you start with a 5.0l block. While I have no trouble revving mine to 6,000 rpm, the bigger diameter main journals in the 351w don't truly lend themselves to extended high rpm operation. If you are building a track car, this is something to think about too. Don't get me wrong, I like it, but as someone who likes to tinker and experiment with different intakes, heads, headers etc., I think I would have had an easier time all along if I'd started with a 5.0l engine. I'd probably opt for the shorter stroke 331 and build it for bulletproof high rpm operation. I'd happily trade away the torque if that meant I could do away with some of the other things you simply have to endure when choosing the 351w.

My opinion only, I suspect not a popular one, but you get what you pay for! :D

Sean

[Jim1855]

I've had my 351w/427 in for test fitting and development.
You'll need a low manifold and air cleaner to get it all to fit under the normal hood and scoop.
I have no expectations of being "normal".
Jim

[mike223]

I figured no Purple & Gold Bleeding Louisianian would be on the roads and they weren't so I let her rip.

At 3,500 RPM's 4th gear got interesting and Thank God I still have the rev limiter set at 4,300 so it settled quickly.

Though I'm only making around 450 HP with similar torque figures, the 3.73 ring and pinion makes every gear shift interesting.



I think you're going to want a taller gear when you start spinning it up to 5300~6000 rpm.

I started with a 3.55 gear @ 6500 rev limit + changed to 3.15 gear @ 6000 rev limit.


Because I didn't like (at all) wagging the tail while gently rolling in to half throttle in 3rd gear.


Now I actually have to "get after it" to wag the tail in 3rd - 2nd bumps the rev limiter around 68-72mph.

[rich grsc]

I think you're going to want a taller gear when you start spinning it up to 5300~6000 rpm.

I started with a 3.55 gear @ 6500 rev limit + changed to 3.15 gear @ 6000 rev limit.


Because I didn't like (at all) wagging the tail while gently rolling in to half throttle in 3rd gear.


Now I actually have to "get after it" to wag the tail in 3rd - 2nd bumps the rev limiter around 68-72mph.
I've said before, with these light cars and big HP, low gears aren't the right fit. If I had that HP, a 3:15, or 3:27 gear would be my first choice.

[GoDadGo]

I think you're going to want a taller gear when you start spinning it up to 5300~6000 rpm.


I've said before, with these light cars and big HP, low gears aren't the right fit. If I had that HP, a 3:15, or 3:27 gear would be my first choice.


3.73's is where I need to be since my 5th gear overdrive is a .75 with 6th going all the way down to .50.
This equates to 1,700 RPM in 6th which scoots the car to 70 MPH or 3,400 RPM at 140 MPH.
No matter what speed I'm going the car has the perfect gear for cruising.
The happy operation range is 2,000-6000 with Redline at 6,500.
I just need to learn how to drive the sucker better.

[GoDadGo]

I really think you can't go wrong with a 302, 331, 347 or a 363 combo of the short deck engine; however, the 351 Windsor just looks really great and fills the engine bay nicely.

[GFX2043mtu]

I’m running a victor jr intake on my 461w with a 11” Randy’s racing filter spun aluminum base that I trimmed to be a little lower with a 2.12” tall k&n filter with a k&n filter lid and it fits in the scoop just fine. My oil pan bottom pan is level with the frame rails using the FFR energy suspension poly mounts. When you do your body work and figment just make sure to shim the motor first to make sure the filter fits in the scoop. Once this is done you can then fit the side pipes. I can 100% guarantee you can can run a air gap style single plane intake. Just if you go this route know the pros and cons of such a set up. Personally I suggest going at leat with a 351w if not a 408w or 427w. You can get short blocks through turn key engines through any reputable vendor. It’s easy to make a little more power now and control it with the little flat pedal on the right, then to go back into a motor to make more later. Plus the stock 351w block is much more stout then a stock 302 block.

[NAZ]

https://www.secondstrike.com/technical/aircleanercalc.asp

Use the link above to calculate the affect your short air cleaner is having on your engine's performance.

[CraigS]

A couple of thoughts on 351/408. If you want to stay relatively mild you can use the stock crank and rods. They are significantly stronger than 302 parts and they have one size larger bolts than a 302. Just have them prepped and balanced. Use a set of hypereutectic pistons to get 9.5 to 10-1 CR. Top end kits incl heads, valves, springs, cam etc from companies like Edelbrock easily get you 400+ HP.
https://www.edelbrock.com/shop/power-packages.html?efm=3605&efn=3631&efs=3697
I have a Performer RPM (not air gap) on mine w/ this air filter
https://www.summitracing.com/parts/spe-47622
and have never had a clearance problem. Concerns about the wider overall width are likewise over blown. I made mine into a 408 4 years ago. Yep I know the left rear spark plug is a little harder to get to, but I haven't needed to go there in these 4 years. So don't worry about it. Oh, I halved the price of my cam, springs, pushrods kit by going non-roller. I used break in oil and break in additive for the first 500 miles and just break in additive for the subsequent oil changes. I started w/ a 331 rear gear for the 351 and left it w/ the 408. When I did the IRS upgrade I couldn't find a 331 so got a 315 for a better price since no one seems to want them. The 408 probably could have used a one step wilder cam because I can go around neighborhood corners in 3rd at 1200 and drive away. This engine w/ a TKO 500 w/ stock gears (same as a T-5) is a fantastically street-able engine. I take people for rides and drive around at 1/2 throttle for a while. When the situation is right I ease up to 2500 in second and nail it. As the rear end wiggles all the way through 2nd, the reactions vary depending on their back round, from laughing their *** off to a look of fright. I love it.

[Richard Oben]

Bone stock 351 lower end with TFS cam and heads can run mid 11s on street tires, YES, Street tires. One of our customers ran 11.73 all day on BFG 255 60 15s, but he is also an excellent driver. Stroked 351 cars almost need a way to de torque them. Lower numeric gears, short intakes (good for clearance). This is all to make them more drivable. I know there is no such thing a too much HP but as stated above the tires breaking loose in 3 gear can be a bit of a scary thing. I have driven all kinds of power in these cars 302, 351, 408, 460+ big block. A lot of torque in a 90 inch wheel base requires max attention. It think the sweet spot is between 350 400 at the wheels max. More can be fun but a bit much. JMHO, Richard.

[Avalanche325]

I can't wrap my head around the 347 and the way you have to relieve the block, and the way the bottom ring protrudes when the piston is down.

1. The relief in the block is a tiny knotch about the size of the tip of your pinky in the piston skirt and edge of the block.
2. The rings do not protrude out of the cylinder. On some pistons, the oil ring goes through the wrist pin hole. It is not even remotely an issue.

Guess what you have to do to a 351 when you stroke it? The exact same thing.

[TBull]

Using a boss block or a dart block, you can have a 347 big bore. Great rod angle too. Crank and rods from 331 with 363 pistons. No wobble at the bottom of the stroke, great power and no clearance issues with the hood. Just as an alternative.

[Avalanche325]

I scared myself the other day when wheel spin occured in 4th gear because it was a little cool (65 F) on that day.

What tires are you running?

[GoDadGo]

What tires are you running?

Nitto 555's 285/40-17 with a 300 treadwear.

A softer tires would help; however, I like the taller sidewalls.
Almost gives my car that 15" look since I'm sporting 245/45-17 up front.
I had them on my Old Beloved 1995 C-4 and loved them, but that car only made 300 HP & 330 Torque.

Owned The C4 From 1995 until 2018
https://youtu.be/svZX2BMSDEs

[Avalanche325]

Well, you know the deal. Stickier and wider is what these cars need from a performance and safety perspective. Personal opinion is 200TW for over 300hp.

To the OP.
351, compared to a 302 what are you in for.
1. A little more expensive.
2. A little less clearance. All been done before, so no big deal.
3. A bit more power at stock CI.
4. A little more weight. Static and rotational.
5. There is some more strength which is good, but the larger journals have higher bearing speed which is bad. Nothing in life is free.
6. Calmer engine at a given HP.

The reason that a lot of builders are going to aftermarket blocks for engines that are not high HP or larger CI, is that good non modified blocks are getting harder to come by. Get a DART or Boss block and it is good. Straight, no cracks, etc.

I have a stock block 347 putting out around 500hp. I autocross and track along with lots of street, so it gets driven hard. These days, I would probably do a DART block 427 to get the same or a little more power and be a little calmer. (and to put my 427 badges on that have been on my desk for 5 years - LOL) My engine is fairly radical and VERY loud. The loud gets old pretty quick. That adds about $2200 IIRC and a little weight.

[GFX2043mtu]

NAZ, With the filter lid I measured the actual filter area not including the wicking of the molded rubber up the filter and the carb stud mount on the lid. I have a total real filter surface area of 98 square inches. This is with in 1 square inch of running a 14” x 3” filter. I have 1/2” - 1.25” of clearance up top on the scoop. Plus it’s been dyno proven that surface area does not mean as much as directional flow and minimum height over the carb. Engine masters did a dyno shoot out showing this. With an equal surface area and a potential for better directional flow I expect to be not to far off there 14 x 3” k&n data, which is recommended for 675hp. My plan is to do some tuning in the spring so I’ll do a with and with out filter run for comparison. I expect to loose power as you just about always do with a filter but how much can only be proven on a dyno. A theoretical calculator is great I just trust real world results from a dyno testing more.

[Avalanche325]

The Engine Masters air filter shootout was very interesting. I love that show. It certainly shows a lot of old school rules to be nothing but old wives tales.

I think what GFX is talking about it this:
They put a round K&N filter on and did a run. Then they put the K&N filter top on and gained power. Then they taped off the outside of the filter, so all of the air was coming through the filter top. That run was the same as everything open, showing that it was sucking all of the air through the top.

I really should ditch my Cobra oval for a top filter.

[Mugzilla]

Thank you all for the input! Y'all even got into gear ratios!

I think a 351 will be in my future. I'll keep the compression down to sacrifice "some" torque to aide in not breaking the tires loose in 3rd gear!

[NAZ]

Since the importance of flow direction into the carb main body was brought up, there's another thing to consider when dealing with hood clearance issues and short air cleaners. Rule of thumb: you need minimum 2" clearance from the bowel vent tubes to the top of the air cleaner cover for the vents to work properly (may not be an issue if using the open top style filters). Less than 2" (this is not a hard measurement) and you can see fuel bowel level deviations causing mixture variation. A more restrictive filter (or heavier breathing engine) and this 2" minimum may increase.

Want to do a real hood scoop and it gets way more complicated as critical speed comes into play.

And one last thing -- dynos are great tools and may provide even more accurate info on filter restrictions (and other performance variables) than a calculator or modeling program can. However, dynos are static testing devices and WILL NOT simulate actual conditions an engine sees in a car. That includes air filtration devices. So just take that into consideration -- a dyno is a powerful tool but is not giving you actual in-use performance data like a drag strip will. I often see folks rely on dyno numbers as if that was the touchstone for all things engine performance wise. Until you can simulate acceleration and aero effects on a dyno you will have to take their limitations into consideration.

[Avalanche325]

NAZ,
Now that you brought vent tubes up. I have told this before, but it is a good warning.

I used a Cobra oval air cleaner as many of us do, on a Quickfuel Q series. It has flat topped vent tubes. The stock filter is very short. I was having severe flooding issues after my engine got warmed up. The filter top was so close to the vent tubes that it would seal them off when getting hot. I went with a taller S&B filter and all is well.

[johnnybgoode]

The Engine Masters air filter shootout was very interesting. I love that show. It certainly shows a lot of old school rules to be nothing but old wives tales.

I think what GFX is talking about it this:
They put a round K&N filter on and did a run. Then they put the K&N filter top on and gained power. Then they taped off the outside of the filter, so all of the air was coming through the filter top. That run was the same as everything open, showing that it was sucking all of the air through the top.

I really should ditch my Cobra oval for a top filter.

And the Salad Bowl came second! MT the best $5/mo. I spend! Scott

[johnnybgoode]

A couple of thoughts on 351/408. If you want to stay relatively mild you can use the stock crank and rods. They are significantly stronger than 302 parts and they have one size larger bolts than a 302. Just have them prepped and balanced. Use a set of hypereutectic pistons to get 9.5 to 10-1 CR. Top end kits incl heads, valves, springs, cam etc from companies like Edelbrock easily get you 400+ HP.
https://www.edelbrock.com/shop/power-packages.html?efm=3605&efn=3631&efs=3697
I have a Performer RPM (not air gap) on mine w/ this air filter
https://www.summitracing.com/parts/spe-47622
and have never had a clearance problem. Concerns about the wider overall width are likewise over blown. I made mine into a 408 4 years ago. Yep I know the left rear spark plug is a little harder to get to, but I haven't needed to go there in these 4 years. So don't worry about it. Oh, I halved the price of my cam, springs, pushrods kit by going non-roller. I used break in oil and break in additive for the first 500 miles and just break in additive for the subsequent oil changes. I started w/ a 331 rear gear for the 351 and left it w/ the 408. When I did the IRS upgrade I couldn't find a 331 so got a 315 for a better price since no one seems to want them. The 408 probably could have used a one step wilder cam because I can go around neighborhood corners in 3rd at 1200 and drive away. This engine w/ a TKO 500 w/ stock gears (same as a T-5) is a fantastically street-able engine. I take people for rides and drive around at 1/2 throttle for a while. When the situation is right I ease up to 2500 in second and nail it. As the rear end wiggles all the way through 2nd, the reactions vary depending on their back round, from laughing their *** off to a look of fright. I love it.

2X I run the standard non air gap Performer RPM intake as well and it makes great power with no clearance issues. I even have enough room to run a 1/2" spacer. Go with a nice mild 408 kit, you will be very happy. https://www.youtube.com/watch?v=vAuWJqgNFI4 Scott

[mike223]

Now that you brought vent tubes up



Heh - if you understand vent tubes, you won't be able to "unsee" the Holley Avenger vent tube.

Along with the typical "whistles" - this prevents heavy acceleration, or mostly heavy braking (and to a lesser extent other g force) related flooding / rich conditions.


(no I'm not selling them, lol)


Couldn't get image to load - search google.

[bobl]

I just finished helping my brother build his Mk3.1. I built a pretty mild 351 with stock crank and rods, but used AFR 185 heads. It made 475 HP at 5800 rpm. Here's the kicker. We used an Edelbrock RPM Air Gap dual quad intake with dual Fitech throttle bodies and an oval cobra style air cleaner. It fits nicely in the scoop recess. I had to cut the base and reweld the holes because the Edelbrock intake has the mounting pads closer together than the cobra intakes. But that gave me an opportunity to slide the whole assembly further forward providing clearance for the Vintage air A/C box. I'm sure the filter is quite restrictive at high rpm, but you'll never see that on the street and you can always remove the air cleaner at the track If you're chasing that last 25 hp.

So, I've driven his car quite a bit and can offer an opinion. My car has a 347 making over 500 HP at 6700 RPM. The 2 cars drive much differently. His has 4.10 gears, mine 3.55. I like the way his car cruises at low speed because of the gears, but at hwy speed mine is much happier. As far as acceleration his car is violent but hits the rev limiter very quickly in any gear. My car comes on less aggressive and pulls harder to a much higher rpm, which I believe keeps the tires hooked up a bit better. So to me anyway, this confirms that gobs of low end torque is not your friend in one of these cars. So, I quess the bottom line is build what you want and learn to drive it.

[CraigS]

1. The relief in the block is a tiny knotch about the size of the tip of your pinky in the piston skirt and edge of the block.
2. The rings do not protrude out of the cylinder. On some pistons, the oil ring goes through the wrist pin hole. It is not even remotely an issue.

Guess what you have to do to a 351 when you stroke it? The exact same thing.
My 84 block did not need any grinding w/ my 408 kit. Could be that different brand cranks vary whether they need it or not.

[mike223]

My 84 block did not need any grinding w/ my 408 kit. Could be that different brand cranks vary whether they need it or not.



Just another point of data:

My 1990 block did require a little grinding at the bottom of (at least) most of the cylinders for the 393w crank - specifically it was to provide clearance for the bolt heads on the h-beam rods as they pass the outside bottom edge of the cylinders.

[GoDadGo]

I just finished helping my brother build his Mk3.1. I built a pretty mild 351 with stock crank and rods, but used AFR 185 heads. It made 475 HP at 5800 rpm. Here's the kicker.

So, I've driven his car quite a bit and can offer an opinion. My car has a 347 making over 500 HP at 6700 RPM.

The 2 cars drive much differently. His has 4.10 gears, mine 3.55. I like the way his car cruises at low speed because of the gears, but at hwy speed mine is much happier. As far as acceleration his car is violent but hits the rev limiter very quickly in any gear. My car comes on less aggressive and pulls harder to a much higher rpm, which I believe keeps the tires hooked up a bit better. So to me anyway, this confirms that gobs of low end torque is not your friend in one of these cars. So, I quess the bottom line is build what you want and learn to drive it.

Great Perspective Having Ample Seat Time In Both Cars!

[rezell3d]

Agreed. Stay away from the Performer Air Gap intakes or others of the same height and hood to air filter clearance will be OK.

Jeff

I want to use the Edelbrock Victor intake on my Windsor build. Will I have any problems with clearance?

[GoDadGo]

I want to use the Edelbrock Victor intake on my Windsor build. Will I have any problems with clearance?

The shortest intake for a 351-W, especially if you are looking for a single plane intake, is the Torker II.

https://www.edelbrock.com/torker-ii-small-block-ford-351w-intake-manifold-5081.html

Hope This Helps!

[erstanl]

My 84 block did not need any grinding w/ my 408 kit. Could be that different brand cranks vary whether they need it or not.

This was my case as well. My block is an 351W F4TE (1994 truck engine). No clearancing necessary to get to 408 using a cast steel eagle crank.

[CFranks]

My 351-based 427 with rpm air gap intake, carb and oval air cleaner JUST fits under the hood even without the hood scoop (waiting for painter to do that). If I get after it there is the slightest of scrapes but will be plenary of room with scoop.

[Avalanche325]

My 84 block did not need any grinding w/ my 408 kit. Could be that different brand cranks vary whether they need it or not.

Yep, it depends on the specific crank and piston combination and how far you are going. The OP sounded a little freaked out about it. But the first time someone sees a clearanced block, they quickly realize that it is no big deal.

[Dwleo]

A 351 block is a good choice. Many on here will support and recommend. Just watch the height on the intake, carb, air cleaner, etc. Easy to run out of height there and be against the hood due to the increased deck height of the 351 block. .

I had a 351W built for my Mk IV and love it! Only pulling 370 hp but that's more than enough to have fun with. I'm running a spacer under my slayer and the oval cleaner which just fits in the scoop tunnel with only a slight modification.

[Mugzilla]

Yep, it depends on the specific crank and piston combination and how far you are going. The OP sounded a little freaked out about it. But the first time someone sees a clearanced block, they quickly realize that it is no big deal.


I would put me less than freaked out, but losing some cylinder piston guidance gives me cause for concern. Seems a 347 is on the ragged edge of comfort to make the power that a 351w will. Still earning and absorbing from the great conversation!

[CraigS]

I understand why people go w/ a 347 especially if they already own the car/engine. Because of the taller deck a 351 needs different intake and exhaust headers so they would be an additional expense. But if starting w/ nothing, a 351 costs no more than a 302. And, if you are satisfied w/ about 350 cubes, you can use the stock 351 internals, vs a stroker kit to get from a 302 to 347.

[rich grsc]

I would put me less than freaked out, but losing some cylinder piston guidance gives me cause for concern. Seems a 347 is on the ragged edge of comfort to make the power that a 351w will. Still earning and absorbing from the great conversation!
You're talking about a notch about 3/8" wide and about the same tall on the very bottom edge of the piston wall to clear the rod bolt as it swings past. It has zero affect on piston support.

[NAZ]

It's common on strokers (Ford or Chevy) to require a small relief for rod bolt clearance -- not a big deal if done correctly. Want something important to consider when looking at a stroker -- look at rod lengths. Because the deck height is fixed you have to keep the piston travel within the original cylinder length which will require a piston with a lower compression height, shorter rod, or both. Rod length has more affect than folks realize. A short rod can cause a significant amount of friction and pre-mature wear on rings, pistons and cylinder. That friction also robs a lot of HP.

Rod length has other performance characteristics you should be aware of. Longer rods are less prone to detonation, increases piston dwell at TDC, improves combustion efficiency, and produces more power from mid-range to peak RPM.

So don't fret about block clearance mods but do look closely at rod length when considering a stroker. For example, before I built my latest engine I spent many hours with my modeling software to arrive at the bore / stroke / piston / head combo. Since I was building a nitrous engine I was limited on compression height (same for boosted engines), therefore limited on rod length and rod ratio. My 406 actually makes more peak power than the same basic configuration with 434 cubic inches because I can run a bigger rod ratio with the shorter stroke. There's that much less friction with the longer rod ratio (1.6:1 on the 406 vs 1.5:1 on the 434).

[mike223]

Rod length has more affect than folks realize. A short rod can cause a significant amount of friction and pre-mature wear on rings, pistons and cylinder. That friction also robs a lot of HP.


So don't fret about block clearance mods but do look closely at rod length when considering a stroker.



+1

Here's a good reference: https://www.fordmuscle.com/archives/2003/09/stroker/index2.php


Also do not be oblivious to compression ratio - lest you build something that runs better on diesel than regular unleaded...

[GoDadGo]

+1
Here's a good reference: https://www.fordmuscle.com/archives/2003/09/stroker/index2.php


Thanks For Sharing!
I Am Glad I Went With 6.0" Rods Over The 5.7" Rods For My 383.

[NAZ]

Great reference Mike! Particularly for the SBF. And good advice on the compression ratio.

Folks may want to also research dynamic compression ratio if doing their own combining of parts and assembling an engine themselves. The static CR we commonly cite and most pay attention to is only a reference point -- dynamic CR is becomes important when you start pushing the envelope on pump gas. For you amateur engine builder, GTS (Google that stuff) to learn more.

[GoDadGo]

NAZ & Mike223,

I totally missed the boat when it comes to Dynamic CR.
Guess that's the Banker in me, but the car runs very well.

My Static CR Is between 10.00 and 10.125.
I am running iron heads. (Dart 215 CC Intake Runner Iron Eagle Tall Ports With 72 CC Chambers)

383 CID / 4.030 Bore / 3.75 Stroke
6.0" rods in the sucker so my rod angle ratio is 1.6.
12 Degrees initial timing, mechanical advance only, 32 total.

Duration @ 0.006": 288° / 294°
Duration @ 0.050": 236° / 242°
Max Lift w/ 1.5RR: .520" / .540"
Lobe Separation: 110°
Intake Centerline: 106°

Do I have any issues the be concerned about?

[Jeff Kleiner]

Do I have any issues the be concerned about?

You mean other than the distributor being on the wrong end?

Jeff

[Avalanche325]

You mean other than the distributor being on the wrong end?

Jeff

Ha! hahahahahaha!

[GoDadGo]

You mean other than the distributor being on the wrong end?

Jeff

Ha! hahahahahaha!

Correct End For Acceleration Since Da-Sump & Da-Pump Both Get Covered For All Hard Launches.

Totally Wrong End If You Like Stopping More Than Geauxing!

Geaux Tigers!

Geaux Saints!

[NAZ]

Distributor on the wrong end -- that's funny. As a former Ford technician, I have to agree. But working with SBC & BBC engines for so long now it almost looks normal.

Steve, if you don't have any detonation issues now you should be OK until AOC and her friends outlaw 91 / 93 octane pump gas. Dynamic CR is always lower than static as it takes into consideration the point at which the intake valve closes. Compression can't start until all the valves are closed. If you were to add a turbo you might want to revisit your CR or you can change the cam timing or grind to hold the intake valve open longer and lower your dynamic CR.

All is good.

UPDATE:
My bad, I left off some important 411. While the DCR is always less than the SCR, the octane requirement scale is also adjusted when using the DCR. For example, my SCR is 12.97 and my DCR is 10.71. If we were talking 10.7 SCR that would be a pump gas engine with a moderate cam, however, when looking at DCR the requirement is 110 octane minimum and that is also dependent on ECT and alum vs cast iron heads.

But you're still OK on your set-up -- if it's been running good so far, no worries.

[canuck1]

This won't rectify your distributor orientation issues GoDad, but it can be fun to enter your numbers into a calculator to see what you come up with. I have downloaded and use this one frequently:

http://members.uia.net/pkelley2/DynamicCR.html

It's a very useful guide and aid in selecting components, especially camshaft. Make sure to read the technical guide and enter data in the format requested.


Sean

[NAZ]

Canuck1, looks like your attachment must be an old version. Seems like it provides some good info but some of the links to other sites are faulty. David Vizard is one of my heroes and of course I clicked his link first thing. Interesting bunny trail to follow -- not what I expected, but interesting. :rolleyes:

[canuck1]

Naz,

An old link, for sure. I downloaded the dynamic compression ratio calculator from there years ago. The link to download Pat Kelley's DCR calculator is still there, but some of the other links are probably not valid.

There are online sources for similar calculators, but I like having it at hand when I'm curious about a combo.

Sean

[NAZ]

Sean, not everyone appreciates my sense of humor. You should check out David Vizard's link but make sure your virus protection is up to date before clicking past the first page. Enter at your own risk.

[rich grsc]

There is no excuse for a chevy, or forgiveness.:rolleyes: :p

[GoDadGo]

There is no excuse for a chevy, or forgiveness.:rolleyes: :p

.Yep, Chevrolet Never Forgives Where I Live.
They Just Win!

https://www.gulfportdragway.com/ford-vs-chevy/

[Howard]

I'm running a Dart block 427W - absolutely love it - running it with Nitto NT01 tires - soooo much fun. Easy to control the rear end with the right foot.

[Mugzilla]

Thank you all for the input! Y'all even got into gear ratios!

I think a 351 will be in my future. I'll keep the compression down to sacrifice "some" torque to aide in not breaking the tires loose in 3rd gear!

Now I have some thinking to do; If I stroke this thing, I’ll be creating low end torque, which, while fun, can end up NOT being your friend.

[NAZ]

Now I have some thinking to do; If I stroke this thing, I’ll be creating low end torque, which, while fun, can end up NOT being your friend.

It's easier to build power into the engine now than add it later. That skinny pedal modulates the power so don't fret all the talk about tires up in smoke, you don't have to accept that (well, maybe with an IRS). My car has a 6000 RPM stall converter, 3.90:1 rear ratio and on a standard day at sea level will produce over 10,000 lb feet of torque at the rear axle (>600 lb ft of engine torque & >700 HP at 6000 RPM). When I leave from a stop light off the trans brake & two-step there is no drama, no scalded tires up in smoke but it will plant you in the seat with more than 2 G's. The car weighs less than 2500 lbs full of fuel and my pear shaped body in it. It is possible to harness that power and turn it into acceleration with a solid rear axle.

[CraigS]

Now I have some thinking to do; If I stroke this thing, I’ll be creating low end torque, which, while fun, can end up NOT being your friend.
I built a mild 408. I told Comp Cams I wanted to be able to drive at 1300 in 5th. Used their recommended cam. I should probably have gone one step up w/ the cam. But the engine drives perfectly, almost as well as an injected engine. I can drive around at 1300 in 5th or at 1000 in 3rd ambling around in a neighborhood. I also set up my mechanical throttle linkage to have a little more than average pedal travel so I have better control. So I say that, if you want to stroke it go ahead.

[rich grsc]

Now I have some thinking to do; If I stroke this thing, I’ll be creating low end torque, which, while fun, can end up NOT being your friend.
That is the exact opposite of true. Having torque makes it very easy to drive, you don't have to constantly be shifting, and easily rolling into RPM's make for a smooth steady drive.

[Jeff Kleiner]

Every throttle pedal I've ever used operated like a hinge---they swing both ways, up AND down. ;)

Jeff

[GUARDDOGG]

Even if I run a FFR hood scoop?

[rich grsc]

No, you can't run a hood scoop

[NAZ]

Run without a hood. Problem solved. What else can I help you with?

[CraigS]

Even if I run a FFR hood scoop?

What does this mean?

[AdamIsAdam]

I can't help but show off like a proud pappa and add to this thread:

I just had my 347 stroker on the dyno last week. I could not be happier with the performance. FLAT torque "curve" and HP that just points to the sky. This engine is fantastic. It's got 10.5:1 yet starts and runs like it's 8:1. It's got gobs of power everywhere. Yet that 302 block gives me enough room to work on it and looks great.

Oh, and I was really curious to see how badly my 1.75" oval air cleaner was choking it so my runs were: #1) air cleaner on, hood open. #2) air cleaner off, hood open. #3) air cleaner off and hood closed. I made the most power on #3! I suspect it made more power as it got fully heat soaked, but I went up 5hp with each run, making the most with the air cleaner on.

385HP at the wheel, so approx 450+ at the crank. And with 3.55's and a T5 with .6 overdrive (73 MPH @ 2,000 RPM) and it loves to run at all speeds, all RPM's, etc.

https://youtu.be/6hhnwAYj-Jc

https://youtu.be/QboLm0fO7Yo

137207

[CraigS]

An Edelbrock Performer RPM (not air gap) w/ this cleaner works fine.
https://www.summitracing.com/search?SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=Spectre%20Performance%20ExtraFlow%20Air%20 Cleaners%20SPE-47622

[Rdone585]

What am I in for?=> too much fun!

Based on my experience with a stock 351W block, don't go too high in HP. If you keep it under 500 HP you will probably be OK. Consider a crank girdle for a measure of insurance. If you want more I'd suggest an aftermarket block that will handle the torque and HP, like the Dart SHP. I tore the block apart where the crack main bearings bolt to the block. Chunks of block floating around the engine = failure. Admittedly this was WOT on the straight at a track, so that equals maximum stress on the 2 bolt mains. All said and done, I say go for it, build the engine of your dreams, you will not be disappointed. If you need an Eagle crank for your build, I have 2 good spares, one for a 351W and one for a Dart SHP. I can share the stories of why if you care to hear.