2004 Ford Mustang GT with 4.6 2v - Bad Donor?

[Denvershelby]

Father and Son bought an ‘04 Mustang GT to use as a donor. TR-3650 transmission and 4.6 liter 2v engine. Came from factory at 260 hp, which I assumed was plenty for my FFR (we’re not racers). I thought I’d do something to boost to maybe 300 hp, but now that seems expensive and maybe pointless. Now I feel like I did in the shower after the summer before 7th grade...all you guys with 500, 600, 800+ hp, and here I am with less than 300. Did I make a bad choice for a donor? Any mods you’d recommend? If we go with this, will the other guys point and laugh? Thank you.

[i.e.427]

We completed this car last year for a customer. It has the later generation 3V 4.6 and I absolutely love the way this car drives, 4.6 is an awesome engine. Would you laugh at this?

https://live.staticflickr.com/65535/49359373077_47fb81e13c_k.jpg (https://flic.kr/p/2icHFXK)20180929_100517 (https://flic.kr/p/2icHFXK) by i.e.427 (https://www.flickr.com/photos/152631091@N02/), on Flickr

[wallace18]

It will do just fine. 200HP in an MK4 is fun.

[Jeff Kleiner]

You'll be just fine! Big HP numbers are great for bragging rights at the cruise in but I can assure you that you'll have more fun than lots of those guys :) Do your research here; there are some nuances &/or challenges with using the 1999-2004 era cars that you will want to make yourself aware of such as the wide rear end and spindles, etc. Not insurmountable at all but plan for them ahead of time rather than getting hung up on them later.

Good luck!

Jeff

[walt mckenna]

Father and Son bought an ‘04 Mustang GT to use as a donor. TR-3650 transmission and 4.6 liter 2v engine. Came from factory at 260 hp, which I assumed was plenty for my FFR (we’re not racers). I thought I’d do something to boost to maybe 300 hp, but now that seems expensive and maybe pointless. Now I feel like I did in the shower after the summer before 7th grade...all you guys with 500, 600, 800+ hp, and here I am with less than 300. Did I make a bad choice for a donor? Any mods you’d recommend? If we go with this, will the other guys point and laugh? Thank you.

I did not like the ratio spread on the TR3650, so I switched to a TKO600, otherwise I have been very happy with the performance.

[GoDadGo]

If you used the stock rear end, I think you can make it work by using wheels with deeper offsets.
Mustang wheel choices from 2005-2009 have a much deeper offset than those from the previous body type.
With that said, you likely will be able to find some nice looking wheels

Possible Front Wheel
https://www.americanmuscle.com/verde-2005-18x9-black-deep-dish-bullitt-wheels.html

Possible Rear Wheel
https://www.americanmuscle.com/black-2005-deep-dish-bullitt-wheels-18x9-18x10.html

You'll be shocked at how quick your 4.6 will be once it sheds well over 1,000 pounds once it is transplanted.
Think of your Horsepower to Weight Ratio and a little power will go a long way.
Good Luck From The Dark Dart Side!

[Paul2STL]

The 04 Mustang is probably not the best donor, mainly because most of the parts are unusable. And the one that are may not be the ones desirable to use depending on the look and performance you are wanting. I suggest do a lot of research on this forum and ffcobra forum. Just a few examples of part that are not choice are the rear axle is too wide to use FFR Halibrands and they will stick out. The spindles are not the best ones use to get the right geometry. There are other things also. In the end you end up not using much from that car. A lot depends on your budget and what you want to use the care for. The best advice before you do anything is research, research and research.

[skidd]

Not quite the same motor.... but I'm in a similar(ish) place.. I'm making maybe 300-350 HP (haven't been on a dyno yet) out of a '99 302 with an e303 cam, decent intake and vac-secondary 600cfm carb & 3.55 rear end. And I promise you, the car is a freakin' BLAST to drive. Do I wish I had more power? .. sure. for bragging rights.. but.. I sure don't need it. 1st and 2nd gear easily overwhelms the tires, 3rd has no problem spinning them with an aggressive clutch-dump. Plus with the alphabet cam, it makes a nice rumble at idle.

Not sure how good they are, but I know CompCams makes a few 2v cams. I presume they would be a decent upgrade to the stock ones.

In fact, before I found the 302 I currently have, I was really looking to go with a 4.6 in my car. I was going to use the Edelbrock Carb Intake Manifold, find a good 600cfm carb, and perhaps do a cam swap.

Also.. with the fact that the 4.6 can handle higher revs.. going with a good rear end ratio will make a huge difference too. 3.55? perhaps the 3.73? dunno

[Avalanche325]

It will be a Cobra, it will be fun to drive, and it will get thumbs up all day long at any HP level. How much power you "need" depends on what you do with the car and more importantly, your driving skills.

The issues with a 4.6 are that there isn't a lot of aftermarket support, so upgrades can be pricey. Not the best engine for resale value. Besides that, there is nothing wrong with a 4.6.

The biggest thing I would think about is the future of the car. Are you going to want more HP, different wheels, etc? The upgrade path can be more expensive than building what you really want to end up with up front. Not that the upgrade path won't be fun, or even be exactly what you want to do. Just don't build something that you don't really want. That's how cars get sold cheap.

As far as the donor, work up a comparison of donor vs non-donor. I was originally thinking of doing a donor, but changed my mind for both financial reasons (it just wasn't cost effective for me with thinking of using a Fox), and I didn't want a new car with 20 year old parts.

[Indy Shu]

I built mine 14 years ago with an '02 GT and used most of the donor parts except for the dash/gauges. Later, i did end up swapping the rear so i could go with wider wheels, and have done some upgrades since. Not necessary, just tinkering. Always starts right up, always runs great. If in decent shape, a donor still has good value in engine, trans, hydroboost/brake system/power steering, radiator, fuel tank & pump. While driving, i have never thought i needed more HP.
I would recommend sending the wiring harness to Wire Diet. Art will do a great job of tailoring it to the build. Keep on your path unless you want to spend a lot more $.

John

[totem]

I started my build with a gently rolled over 03 GT bought for 1600$ cad. Used engine, transmission, fuel thank and parking brake. I cleaned up the wiring my self.

I suggest you buy FFR front knuckles and buy a differentrear end.

Rear end should be a 87-93 converted to 5 bolts or a 94-98 rear end with shorter axles. Build it with 3.55 or 3.73 gear. Rear end and gear are easy to find used for cheap.

260hp is plenty of fun. It was cheaper and allowed me to put the car on the road quicker given cashflow. I later upgraded to a Coyote with keeping the same drive train. Then painted the car. This way, car was on the road after 18 mo at 50% of full cost. With 100% build achieve over 42 mo.

The main drawback with the 4.6 2v is that it makes a ugly engine bay...

[AtlantaCobra]

Father and Son bought an ‘04 Mustang GT to use as a donor. TR-3650 transmission and 4.6 liter 2v engine. Came from factory at 260 hp, which I assumed was plenty for my FFR (we’re not racers). I thought I’d do something to boost to maybe 300 hp, but now that seems expensive and maybe pointless. Now I feel like I did in the shower after the summer before 7th grade...all you guys with 500, 600, 800+ hp, and here I am with less than 300. Did I make a bad choice for a donor? Any mods you’d recommend? If we go with this, will the other guys point and laugh? Thank you.

I've got the 4.6 in my Cobra and love it. It's the 4V version out of a 2004 Mach 1. Had it tuned and I'm getting about 335 HP. I had a previous Cobra with a 351W in it and I have to say I like this 4.6 much better. Fuel injection and a modular engine make it so much more dependable and I'm not constantly looking at my gauges for oil pressure and over-heating like I was with my 351W. Awesome sound too and it spins up faster.
Plenty of HP and quick out of the hole, which is really the fun part of high horse power(in my opinion). Under the hood doesn't look quite as impressive as a built engine, but there are some mods to make it look pretty good. The modular engines are popular, obviously with Coyote being placed in so many cars. I see my 4.6 as the beginning of this trend.
-Greg

[Joecobr]

I don’t think the 4.6 looks too bad. This is the ‘98 Cobra 4.6 4V in my car.124324

[cob427sc]

I built one in 2000 I believe with a 4.6 two valve. One of the first using this engine and took some mods to the steering and frame back then. Engine ran great once I got around the anti theft which required use of the original ignition switch and key. Solved the problem with a ECU from a police cruiser which did not come with the anti theft. Lots of fun and plenty of power for normal driving. Someone out there must own the car now - yellow, black stripes, American Racing wheels, dual chrome roll bars.

[Denvershelby]

Thank you all for the perspectives! I’m much more confident and excited!

[initiator]

I drove a 2003 Mustang GT for 6 years with 260 HP. Great sound through the 'sport' exhaust and enough power for most situations. Car weight is around 3400 lbs for a weight-to-power ratio of 13.1. My current car has 390 HP and 3600 lb, weight-to-power of 9.2. In this car, you can mat the gas pedal for maybe 3 seconds before you're getting into legal/safety issues. And that's with lots of weight to keep the rear tires planted.

The Mk4 weighs 2200-2400 lbs, so your 260 HP matches my car at 9.2 weight-to-power. It's plenty of power for an exhilarating ride, especially if you haven't driven a car like this before. The Cobra's short wheelbase and lack of weight on the rear tires mean you're going to run out of traction before you run out of power, unless you significantly elevate your tire selection and driving skills. For cruising and the occasional straight line blast, I think you'll be very happy.

[Denvershelby]

Would you mind sharing details on how you cleaned up your wiring? The harnesses are monstrous!

[cfriedman67]

Contact Art at www.wirediet.com. I used him. its not cheap but he makes it very easy.

[walt mckenna]

Contact Art at www.wirediet.com. I used him. its not cheap but he makes it very easy.

You send Art the ECU and all the wiring along with instructions on what systems to keep and which ones to eliminate (Art will question you on this). He will remove excess wiring as needed, modify ECU as needed, fully test, and return to you will all things labeled. I was originally reluctant to spend the money, but in retrospect, it was a bargain. The modified harness fits the chassis well and it works. Do not hesitate to have Art do this work for you.

[Joecobr]

I used Art’s services as well. Can’t say enough good about him. The wiring was dieted right down to very little and it was a piece of cake tying it into the Ron Francis wiring. In this build I was most apprehensive about the wiring. Turns out it was the most enjoyable for me because I was able to over come the mental block. The car started up first turn and the complete electrical system worked perfectly.