Donor build questions

[Reubster24]

I'm looking to build my first roadster. I have access to a cheap donor 2000 mustang. For those that have built using a donor is there a lot of value in going with a complete kit vs basic? If I go basic is there anything I should consider adding that would be highly recommended? The one thing I don't quite understand is the gauges. With the basic kit using a donor does it use the factory mustang gauge cluster? Also with the donor what is done about the cats? Does it run right without them or do I have to get custom programming. Any recommended mods to do to the stock engine before putting it in? I'm still debating on rebuilding it or leaving it as is. I don't really want to sink a ton into the engine/trans since it will defeat the purpose of using a donor car. But since I got the whole car for $1500 I have a little room. I thought about rebuilding myself and adding cams, injectors, throttle body, and intake to try to get it up to 300hp. Are the wilwood brakes worth it or do the stock mustang ones work fine. Thanks in advance for your help.

[Alan_C]

I used a 2004 Mach 1 for my donor, it was 7 years old at the time with only 38K miles. It made a great donor as I did not have to rebuild all the donor brake and other parts. The main complaint I have read about donor builds is often the builder had bought a cheap worn out donor, then finds out most of the parts are worth little more that cores for remanufactured parts. Buying my Mach 1 provided a engine with 320 HP stock and larger front brakes than the complete kit supplied. For me the donor approach with a base kit worked. Given that the MK4 was designed for donors no newer than 2004, good donor cars worth using are getting harder to find. I believe this is why you see fewer donor builds today. If the modified 2V 4.6L with some add ons is enough power for you, your plan could work out. I found the TR-3650 to be a decent transmission. I upgraded the 8.8 with a TruTrac differential, something I believe is worthwhile.

Good luck,

Alan

[Jeff Kleiner]

The 2000 rear end is too wide; you would either need to have it narrowed, run small tires on narrow rims or use custom rims with non-standard offsets (which can get pricey). The 200 spindles will work but are not especially desirable due to less than ideal geometry and again, they are wider and can result in tire fitment challenges. The Mustang gauge conversion that is included with the base kit is for 1987-1993 Fox body cars and is not compatible with 2000 gauge cluster. Dieting the 2000 Mustang 4.6 harness is a pretty significant undertaking that also involves defeating the PATS anti-theft system. If you aren't especially comfortable with wiring and interpreting schematics you might want to consider sending it off to Art at http://wirediet.com/. Not inexpensive but it will be "plug and play". Either way you'll have to tune around the deleted cats.

Good luck,
Jeff

[cfriedman67]

I bought a used 1997 cobra engine, harness, etc... I wound up junking then engine after getting the harness wire dieted as the engine turned out to need to much work. This was entirely my fault for not looking into it sooner. If you have the expertise to rebuild go for it. I do have the complete wire harness all cleaned and dieted from Art Cuesta at wirediet.com if you plan to go that way and if it is compatible with your 2000. If you have an interest let me know as I would sell it cheap.

Regards

[cob427sc]

I have built roadsters both ways and I must admit that the complete kit saves a lot of time and frustration that comes during disassembly, cleaning, painting, etc. I did build one using a 2000mile 2002 as a donor that wasn't too bad as being new everything was clean and came apart easily. I did my first using a 48,000 mile donor and it was a pain going through the process. To me, stripping the wire harness was the worst as you basically have to remove everything in the car to get it out. If you can afford the money, go with the complete kit and save a lot of time and busted knuckels.

[Avalanche325]

I originally thought about a donor build. I am glad I didn't. It is one thing to use an older engine / transmission that you can pull out of the car in two hours if needed. It is another to build a car with 20 year old wiring. I wouldn't do that for any reason.

The only thing bad I have to say about a 4.6L is that they are pretty much orphaned these days.

In my book, Wilwoods are worth every penny. I do autocross and track my car. But, I have yet to see a car that stops too fast. One foot can be all the difference. You can beat on them all day at the track with no overheating.

[CraigS]

I might pull the engine/trans from the donor and sell the rest of it. Or,,,I would have to research it a lot more but the list of obstacles to over come to use that engine, as have been pointed out above, I'd probably sell the whole car. Personally, I'd rather look around for a more mainstream engine. A 302 or 351, or go whole hog and use a Coyote. As Jeff said the donor rear axle is too wide so the cost of narrowing needs to be included. The donor front suspension won't work either. Over the years the FFR front suspension has evolved from using parts that can be made to physically fit together to a well engineered design using spindles specifically designed by FFR for their cars. These are just a couple of examples of why a donor build really isn't a great way to go any more.

[CaptB]

I too thought about the donor option. But in the end I wanted all new parts and didn't want the hassle of refurbishing anything. However, it's up to how much time and if you want to spend that time refurbishing old parts. Good luck either way.

[Reubster24]

Thank you guys for your help. I'm certainly second guessing the donor build. By the time I get the wiring and rear axle figured out it sounds like I'm better off going with complete kit. I'm thinking of getting a 351w and building it myself into a 427. Tkx trans and refreshing a correct width axle. It's going to cost at least 10k more but in the end I'll have a way better car with double the horsepower.

[Morrisett]

We’ll I’ll be one of the rare ones and tell you I’ve enjoyed my donor build thus far. I used a 97 cobra donor in great condition and used quite a few of the parts/pieces that I think saved me a bit. I was able to recoup over half the cost of the donor from selling other parts and still have more to sell. I did narrow the rear axle as recommended and replaced all the bearings/seals which I think was a fraction of the cost of a new 8.8. I also followed a lot of the guys suggestions on this forum on upgrades and where it was important to use ff options (complete front / rear suspension). I used Art for a wire diet and yes he’s not free but worth every penny imo for how easy it has been to wire. I understand why the donor option is dying off but it seemed the right path for me and I proud of my build as it stands. I will say having car lift made the dissemble of donor much easier from start to finish (drive train, wiring harness etc). Either way I am sure you will enjoy your build.

And to answer a few of your questions-
I used speed hut gauges (like supplied in ffr upgrade option)
cobra brakes / hydro boost- new pads and slotted rotors
No engine upgrades -stock 305hp
Deleted cats and a few other items not needed during the wire diet.

[Alan_C]

I also enjoyed my donor build, but as I mentioned in my previous post I found a great donor ten years ago for the build. As time goes on, fewer suitable donors are going to be around. Although the modular engines are good for over 200K miles when cared for, not sure would want a tired engine in the Cobra. I failed to mention that I did need to narrow my rear axle, but not a big issue and I had a TrueTrac installed at the same time.
Suspension improvements in the complete kit are desirable. The tubular front lower control arms and the new spindles are worth the money. Some will buy the complete kit and sell off the parts that they decide to upgrade.
Although having a stroked 351 based 427 sounds cool, consider a bit more conservative 392 or 408. I have read increased piston slap from the longer stroke on the 427 can result in shorter engine life. This can be dealt with by using a more exotic block like from Dart, but up goes the price.
When I built my car starting back in 2011, Dave Smith said in the preface of the build manual that 300 HP was a sweet spot for these cars. I think that number has grown to 400 over the years with the introduction of the Coyote.
Figure out you formula first, then go for it.

[CraigS]

I built a 408 w/ a Craigslist 351 block and a stroker kit. I forget the exact combination but the 393 can be built w/ a stock block, a stroker crank and 302-351 pistons and 302/351 rods. This is the least expensive way to get more cubic inches. A 393 will be plenty even if you don't get to say you have a 427.