Donor Car Questions

[FlyingCobra]

I'm starting plans for building a Mk4. Before I order the kit, though, I want to have a plan in place for the donor car since as I understand it I have to tell Factory Five what I'm doing for donor components. The goal is to do it as a mostly donor car conversion, although I am going to buy some components new (radiator, probably gas tank, etc.). Engine wise I'm going to put in a carb'd 302, so either if my donor car has a fuel injected 302 I'll convert it, or if I get a later donor car with a 4.6 I'll just buy a 302 from somewhere else. I specifically want simple, hence going with a carb'd 302 and a T-5. I've got plenty of experience with electronics and fuel injection, but for this car I just want simple. I won't be reusing the electrical system, I'll go with all new to make that simple.

I've been reading up a bunch of threads on donor cars and I think I've got a few general notes made:

- The Mk4 was designed for an '87-'93 donor car, so that works best overall, the negative being that they're 4-lug and so I'd need (or at least want) to convert them to 5-lug if the donor car hadn't done so already. Plus I'd want to convert to rear disk brakes
- '92-93 had the quicker ratio steering racks, so I might want to specifically target those years since I like quick ratio steering
- '94-'95s might have the best 302s and rear disk brakes, but they have some other nuances and the rear end is wider than what's considered optimal
- The later Mustangs ('96-'04) have better brakes, but also have a wider rear end than the Fox bodies, and have some other parts that won't directly bolt over from the Fox body cars

I've read some folks say that the wider rear ends "won't work", but others say they bolt up fine, it's just that by being wider it may limit choices for wheels and tires - which is correct? I don't care about getting the ultra maximum tire width so long as I can still put some good rubber back there. This isn't going to be something I'm trying to win races with.

I'm somewhat leaning towards the idea of getting two donor cars. Get a newer (say 2000+) GT for the better brakes and suspension components and use those from that newer donor car, including the rear end. Then find an '87-'93 for the engine, transmission, and rest of the parts. Ideally I'd find a Fox body that had rear disk brakes already and that would probably be good enough, but the compromise of two donor cars might make the most sense.

If I wanted to go with a 4.6 then obviously just a newer donor car would be the way to go, but since I want pushrods, this might be a good compromise.

Thoughts?

[bobl]

You can go with a 94/95 donor and swap the axles out to Fox length. They are available from many suppliers. The problem is finding a donor that is not totally junk, for a reasonable price. I started with a 95 donor and ended up only using the rear axle housing, pedal box, spindles and engine block.

[Ray]

1984 drivers side axles from a Ford Ranger pickup for the rear. They just slide in the 8.8 live axle. Use Lincoln rotors (I'l have to look up the year) for the front. Easy cheap 5-lug upgrade.

Ray

[michael everson]

I think you will find when you work the numbers. donors just don't work. your better off with a full kit.
Buy a used 302 and T5
buy a used 94-95 rear and the ranger axles.
Everything else will be brand new.
Mmike

[wallace18]

I think you will find when you work the numbers. donors just don't work. your better off with a full kit.
Buy a used 302 and T5
buy a used 94-95 rear and the ranger axles.
Everything else will be brand new.
Mmike
After building 2 complete kits and 1 base kit I have to totally agree with Mike. Donor route is not the way to go. Just my 2 cents worth.

[Joecobr]

I went with a 98 Cobra as a donor because in Canada we can only buy a base kit. But in hindsight I agree it is not the way to go. I ended up using the engine, transmission, steering rack, pedal box, hydroboost, and front calipers only. I went with the old IRS so had to source those parts separately. I had a pretty good rust free donor but went with a new rad and gas tank. At the end of the day it was not worth the effort. If I had to do it all again I would buy a new Coyote and TKO600 and source the rest used on the internet.

[Jeff Kleiner]

When talking about a carbed Windsor build put me on the no donor bandwagon. That doesn't necessarily mean going to a Complete Kit (although it is my recommendation if you can swing it). If you're on a tight budget go with a base and shop for the preferred donor based components ala carte'; i.e., '94/'95 spindles, '94-'98 rear end with caliper relocation brackets, etc.

Good luck,
Jeff

[CraigS]

If you go donor, don't buy a car, just buy the parts you need. As you have found out, there is no one car that has what you want. You could source each component separately or you could find one of the salvage yards that will put together a pallet of parts from different cars. For instance a 94-95 has the better spindles but the engine has all the wrong stuff on the front and the bell housing is longer. No biggy w/ IRS, but it positions the trans too far rearward and the drive shaft is too short for a solid axle. I mentioned the 'better' spindles but, they are not the best which are the FFR spindles. And the 94-95 spindles need an SAI kit to get them up to the 'better' category. Those kits are now extremely hard and may be impossible to find.

[skidd]

I was 100% in your same shoes. I was convinced I was going to go with a Budget Donor Build, with a few upgrades along the way.
Carbd 302; T5; 5-lug; Disk Brakes; etc...
But, like you, I realized there was no single donor that had everything I wanted.
Knowing I was going to have to use some of a donor, and buy new/used other parts... I stumbled into a Non-Donor base build, and it worked out perfectly.
I found a used 5.0 from a 1999 Explorer (GT40p heads) for a song. After selling the GT40 parts to Mustang Guys, I was sitting on a long-block for only $125.
Found a used T5z from a failed mustang project.. for a song.
Found a used 8.8 with 3.55 gears and SN95 Axles.. yeah.. for a song.
Found a guy almost giving away a set of SN95 spindles and PBR Brakes.
Found a used 1998 Pedal Box.. you guessed it.. for a song.
Used 92 fuel tank; AutoZone rebuilt steering rack with 2.5 ratio; new in-town built DriveShaft; Core-Charge trade-in on used PBR brakes; Used Fox Brake Booster;
Mazda Miata Parking Brake; SpeedHut gauges; Speedway 12 circuit hot-rod wiring harness;
You get the idea.
I'll admit, I'm in fact a bit over my "full donor" build budget, but only by a few grand. And that few grand over, is more than compensated by the fact that I have the build I wanted, with the parts I wanted.. and almost no compromise.
So... if you watch Craigslist like a hawk, and keep an eye out for what you know you want, you'll find what you need!

A thread I started a little while back, in an effort to help others approaching a F5 build from a similar mind set. Including my findings with a few SN95 parts.
https://thefactoryfiveforum.com/showthread.php?27033-Internet-Lore-vs-Results-A-few-things-I-learned-that-I-thought-I-d-share

[FlyingCobra]

Thanks for the thoughts. I can appreciate the benefits of the complete kit. In our case, I'm looking for more of a budget build and it's as much (if not more) about the building experience than anything else.

Craig, I think your point about shopping for the individual parts rather than the complete donor car is more or less where I'm headed. But, if I can find a reasonable price on complete donor cars, I have enough property (11 acres) that having a few parts cars around for the duration of the project isn't getting in my way and we don't have an HOA out where we live in farm country, we just have tractors.

So a couple questions that I still have:

1) The "wider" axles - can they be used as-is or do the spindles actually need to be changed? Just trying to understand this one
2) What years/models had the "best" brakes within that '87-'04 range? I'm assuming 2000+

Basically this will help me determine which parts from which vehicles to target.

[FlyingCobra]

I was 100% in your same shoes. I was convinced I was going to go with a Budget Donor Build, with a few upgrades along the way.
Carbd 302; T5; 5-lug; Disk Brakes; etc...
But, like you, I realized there was no single donor that had everything I wanted.
Knowing I was going to have to use some of a donor, and buy new/used other parts... I stumbled into a Non-Donor base build, and it worked out perfectly.
I found a used 5.0 from a 1999 Explorer (GT40p heads) for a song. After selling the GT40 parts to Mustang Guys, I was sitting on a long-block for only $125.
Found a used T5z from a failed mustang project.. for a song.
Found a used 8.8 with 3.55 gears and SN95 Axles.. yeah.. for a song.
Found a guy almost giving away a set of SN95 spindles and PBR Brakes.
Found a used 1998 Pedal Box.. you guessed it.. for a song.
Used 92 fuel tank; AutoZone rebuilt steering rack with 2.5 ratio; new in-town built DriveShaft; Core-Charge trade-in on used PBR brakes; Used Fox Brake Booster;
Mazda Miata Parking Brake; SpeedHut gauges; Speedway 12 circuit hot-rod wiring harness;
You get the idea.
I'll admit, I'm in fact a bit over my "full donor" build budget, but only by a few grand. And that few grand over, is more than compensated by the fact that I have the build I wanted, with the parts I wanted.. and almost no compromise.
So... if you watch Craigslist like a hawk, and keep an eye out for what you know you want, you'll find what you need!

A thread I started a little while back, in an effort to help others approaching a F5 build from a similar mind set. Including my findings with a few SN95 parts.
https://thefactoryfiveforum.com/showthread.php?27033-Internet-Lore-vs-Results-A-few-things-I-learned-that-I-thought-I-d-share

Really appreciate the insight and I'll check out your post. Nice thing where I am is that there's a lot of good stuff (and a lot of junk) on CraigsList, so this may be the ultimate way to go.

You said you went with the SN95 rear end and spindles... is there a reason you chose those over the later ones? Just trying to understand the decision process there for my search.

[skidd]

One thing that did help drive my choices, I was 100% going with a 5-lug setup. Mostly due to my need to run a set of 17" FR500 wheels. Which I freakin' love!.. and they are cheap too, since they are common on Mustangs.

So...

SN95 (1994 and 1995) are the year spindles you want for 5-lug. You don't want the 1996+ spindles. They have a different shape where the steering rod attaches, and It's my understanding that these spindles push the wheels out more... or something.
https://www.stangnet.com/mustang-forums/attachments/94-95vs96-98spindle-jpg.153405/
I've read that the order of worst->best spindles for an FFR is [SN95(97+) -> Fox -> SN95('94) -> FactoryFive]

As for the rear-axle.. I got a sick deal on a SN95 with 3.55 gears. I was always going to go with a 5-lug setup no matter what I found...
It was actually a Fox housing with SN95 axles and a complete set of brakes, including the mounting flange.
The fact that it was Fox housing is not really important, it's the same.

so..

I grabbed it and waited until it was installed until I could make a choice about axles. So far, the SN95 length axles fit. I'm still in Gel coat, but I've not yet once experienced any rubbing.
The tires I have (315/35/17) sit just inside the lip of the fender. The 275 tires out front however, sit just a hair outside the fender. I might swap them for 255 in the future. I also needed to add some steering-rack limiters to keep the fronts from hitting the F-panel.

[TheBabyBadger]

After building 2 complete kits and 1 base kit I have to totally agree with Mike. Donor route is not the way to go. Just my 2 cents worth.

I'm gonna THIRD this. I bought a donor and SCORED. 1991 FoxBody racecar, 1995 5.0 roller motor, full 5 lug conversion. Sold EVERYTHING but the rear end, bought a Road Runner (Coyote Variant) and a T56 mag and went a different direction completely. My 331 build was as much as a Coyote.

REALLY look into your build before using a 302. Remember = old technology and drivability. Big cam will also be annoying to drive at FWY speeds. Don't go jumping over nickels to save pennies. These builds always start with a donor and end up expensive... You're either gonna build a hoopty or a nice car. I'm learning with these kits there is no real in between.

My 2 cents. For what it's worth...

[FlyingCobra]

One thing that did help drive my choices, I was 100% going with a 5-lug setup. Mostly due to my need to run a set of 17" FR500 wheels. Which I freakin' love!.. and they are cheap too, since they are common on Mustangs.

So...

SN95 (1994 and 1995) are the year spindles you want for 5-lug. You don't want the 1996+ spindles. They have a different shape where the steering rod attaches, and It's my understanding that these spindles push the wheels out more... or something.
https://www.stangnet.com/mustang-forums/attachments/94-95vs96-98spindle-jpg.153405/
I've read that the order of worst->best spindles for an FFR is [SN95(97+) -> Fox -> SN95('94) -> FactoryFive]

As for the rear-axle.. I got a sick deal on a SN95 with 3.55 gears. I was always going to go with a 5-lug setup no matter what I found...
It was actually a Fox housing with SN95 axles and a complete set of brakes, including the mounting flange.
The fact that it was Fox housing is not really important, it's the same.

so..

I grabbed it and waited until it was installed until I could make a choice about axles. So far, the SN95 length axles fit. I'm still in Gel coat, but I've not yet once experienced any rubbing.
The tires I have (315/35/17) sit just inside the lip of the fender. The 275 tires out front however, sit just a hair outside the fender. I might swap them for 255 in the future. I also needed to add some steering-rack limiters to keep the fronts from hitting the F-panel.

This is some great info here, thanks. Curious why you had the "need" to run FR500 wheels? I'm a long ways off from determining which wheels to go for, just curious.

Appreciate the good feedback!

[skidd]

I should have put the word "need" in "quotes".
Translation... FR500 wheels were the ones I wanted, and there were almost no other wheels I was willing to go with. I just really like that wheel look on a FFR.
In a way, I sorta designed my drive-train around a set of FR500 wheels and 315 tires.
To be specific, this kit is what I bought...
https://lmr.com/item/WTK-N1007UBS/1994-04-Mustang-Silver-Deep-Dish-Fr500-Wheel-Tire-Kit
Which.. has gone down in price, and now they (LMR) seem to have more tire choices (like M/T) too.

[FlyingCobra]

I should have put the word "need" in "quotes".
Translation... FR500 wheels were the ones I wanted, and there were almost no other wheels I was willing to go with. I just really like that wheel look on a FFR.
In a way, I sorta designed my drive-train around a set of FR500 wheels and 315 tires.
To be specific, this kit is what I bought...
https://lmr.com/item/WTK-N1007UBS/1994-04-Mustang-Silver-Deep-Dish-Fr500-Wheel-Tire-Kit
Which.. has gone down in price, and now they (LMR) seem to have more tire choices (like M/T) too.

Got it. I figured that was likely the case, thanks.

I'm liking the idea of doing the piecemeal "donor" route like you did, and that might be the way to go. But with enough property, a trailer, and CraigsList, it could also make sense to buy up a few parts cars if the right ones come along. I'll just have to watch and see.

[Dave Howard]

I think you will find when you work the numbers. donors just don't work. your better off with a full kit.
Buy a used 302 and T5
buy a used 94-95 rear and the ranger axles.
Everything else will be brand new.
Mmike


I agree with Mike on the complete kit vs donor. The donor route may have been a good option 15-20 years ago for a budget build but today, a donor could be 25 years old. Any and all the parts coming off a donor would have to be refurbished and coated. The major components (engine/trans, differential) need a complete rebuild. At the end of that exercise, you have refurbished 25 year old technology. I would hazard a guess the cost to get you to this point is not much different than buying all new, complete kit.

[3yearplan]

Just my opinion, but if have a LOT of time, going with a donor or two (or more, heck you have 11 acres) probably will get you where you want to be. But you may end up spending more time pulling parts off the donors, cleaning and painting those parts, they gotta look pretty, and then trying to figure out what to do with the leftover cars and/or parts you aren't going to use. I went with a base kit and still used a lot of used parts. MPS Auto Salvage is one of the places I got a lot of parts from. The prices, even with shipping, were very fair. Just be smart about buying, placing one big order can literally save hundreds on shipping as opposed to making a bunch of smaller purchases. Yes I still had to clean my parts and paint them to make them pretty, but I got the parts I wanted without having to part out and dispose of a few different donors. There is no right or wrong way to go, just go with what works for you.

[Norm B]

I went the donor route 6 years ago. It was a 1995 I bought from an insurance auction for $1001.00. Took what I needed and sold off the rest. Things like airbags and controller, bumpers, fenders, doors with power windows etc sold easily.Made money on the deal. Used that money and the applicable cores from the donor to replace the wear items on the donor parts. New brakes, hubs, inner and outer tie rods etc. Also bought parts off Kijiji. It can be done but, as already stated, donors are getting up in age. Disassembling a 20 to 30 year old car for a few parts is can be challenging.

Norm

[FlyingCobra]

I do realize there's extra work (and time) involved in the donor. What I've done in the past with parts/donor cars for other projects is I've parked them out by one of our outbuildings, taken off the parts I've needed, and then I just put it on CraigsList as a "You-Pull" special, then sold what was left of the entire car at some point. Generally works pretty well as we have a lot of people around here who work on their own vehicles. But the donor with buying individual parts here and there is also appealing, especially as I figure out what I want for an engine/transmission/etc.

Planning to call FFR later today to ask a few questions before putting down my deposit. The whole family is excited about doing the build. My wife's better at sheetmetal work than I am (she got about 3/4 of the way to getting her A&P - aircraft mechanic certification for non-aviation folk). You want to talk sheetmetal and rivet work...

[clancypm]

I went the donor route (1996 mustang cobra that had been rolled) and have no regrets. It only had 65,000 miles on it and no rust anywhere on the car. I felt that it helped my understanding on how to build the mark 4 by taking the mustang apart. I wasn't in any big hurry and took the mustang apart at my dads house in the winter (My garage is not heated but my dads is). My goal was to build it for $20k and I think I'm pretty close to that except for the paint job. Just finished it and got it licensed last week, took me 2 years. I have enjoyed the build immensely. Now I'm worried what I'm going to do with my spare time lol.

[FlyingCobra]

I went the donor route (1996 mustang cobra that had been rolled) and have no regrets. It only had 65,000 miles on it and no rust anywhere on the car. I felt that it helped my understanding on how to build the mark 4 by taking the mustang apart. I wasn't in any big hurry and took the mustang apart at my dads house in the winter (My garage is not heated but my dads is). My goal was to build it for $20k and I think I'm pretty close to that except for the paint job. Just finished it and got it licensed last week, took me 2 years. I have enjoyed the build immensely. Now I'm worried what I'm going to do with my spare time lol.

Build another one? :D

[Avalanche325]

I thought I would do a donor build. I quickly changed my mind when I started to find a donor. Fox body Mustangs are now considered classics. That means that they are either far too expensive to part out, or they are completely worn out. 20+ year old donor parts, wiring harness, radiator, gas tank, etc are too far gone to be worth it these days. Even if you find a donor with 1 mile on it, a 20 year old wiring harness is asking for trouble. There have been several people that have done donor builds and ended up replacing pretty much every donor part in about a year.

It was a great concept back in the day when you could get a basically brand new wrecked Mustang for a donor. Those days are long gone.

[FlyingCobra]

I've gone ahead and placed my order for a base kit. So now we can stop telling me to order a complete kit, and I assume the conversation will move in the direction of "You fool! You'll live to regret this!" ;)

I'll post a separate build thread.

[Jeff Kleiner]

...I assume the conversation will move in the direction of "You fool! You'll live to regret this!" ;)



Not at all! Just select your components wisely. We'll be happy to help advise you what works well, what works not so well and what doesn't work at all. Some of us won't even try to convince you that just because something costs more it must be better ;)

Cheers,
Jeff

[FlyingCobra]

Not at all! Just select your components wisely. We'll be happy to help advise you what works well, what works not so well and what doesn't work at all. Some of us won't even try to convince you that just because something costs more it must be better ;)

Much appreciated. :)

The component selection is the next part. I know I'm going to do a SBF/302 block (whether it's a 302, 306, 347, etc. is unknown), would like a TKO but might go for a T-5 depending, and then an 8.8 solid rear axle, either 3.55s or 3.73s (I think 3.73s would be better) for the major components. I'm ordering the optional lower control arms so then I'll just need SN95 spindles, pick out brakes, etc. etc...

Some of it will depend on what deals I can find on parts.

[skidd]

I've gone ahead and placed my order for a base kit. So now we can stop telling me to order a complete kit, and I assume the conversation will move in the direction of "You fool! You'll live to regret this!" ;)

I'll post a separate build thread.

Now that we have an idea of your experience and confidence level, I think you made a better choice with the base kit.
With the base kit, a budget goal, and a list of Must-Haves, I've enjoyed every single:
- "how do I get that to work?"
- "I need to adjust this to make it work better"
- "I wonder if I should get A or B for this one?"
- "oooo.. now I need to go find a great deal on a X for Y"
etc... you get the idea.
That.. and telling people.. "Yeah, the Kit just comes with Frame, Body, Panels, A bunch of hardware and a big-*** manual.. everything else was me". :)

[Paul2STL]

Many great builds have come from a base kit. I am building mine on the base kit, then ordered a bunch of options and then bought a lot of the awesome vendor parts and made some of my own. Based all my parts on the Anniversary edition and saved almost 10k over all. Sent you a pm just now.


I've gone ahead and placed my order for a base kit. So now we can stop telling me to order a complete kit, and I assume the conversation will move in the direction of "You fool! You'll live to regret this!" ;)

I'll post a separate build thread.

[edwardb]

No need to apologize for the base kit / non-donor build. Has worked for me on two of three Roadster builds builds. A T-5 will work fine if you don't get crazy with power and are mainly a street cruiser. They're light and shift nice. Go for the T-5Z world class version. I think if you run the numbers, you'll find the 3.73 is a little short for the diff ratio. 3.55 is probably the better and more popular choice. You can check the numbers on a calculator like this one: http://www.tremec.com/calculadora.php. Don't forget these cars are in the 2200-2300 lb range.

Sounds like you're really watching the budget. Understood. There are lots of choices that might be "better" but of course add cost. One that I'd highly recommend you look at though is the Factory Five spindles versus the Mustang spindles. The front end geometry is vastly better than even the best Mustang spindles. I've had both and the difference in driveability and specifically bump steer is significant. No adapters and no messing around with bump steer kits.

[FlyingCobra]

I suppose I should've included some of my background when I started.

It's been 17 years since I bought my first car, an '82 Jaguar XJ-S V12 that had no steering wheel, no dashboard (heat and A/C removed), and couldn't move under its own power. I basically rebuilt the car (although left the engine alone), including replacing the TH400 slushbox in favor of a TKO. Put 30,000 miles on it in the first full year I had it, and it never stranded me, although I did have a fuel pump go out and two distributor caps blow up. Both common problems on those cars.

I spent 3 summers during college as a mechanic at a Jaguar shop during college before becoming an engineer in the aviation industry, starting off with spending a few thousand hours running piston engines on dynos. Not entirely relevant, but I've got about 3,000 hours of flight time, mostly in piston twins although now I'm flying a turboprop (Mitsubishi MU-2 for those interested).

I've owned something on the order of 40-50 vehicles (cars, trucks, motorcycles, airplanes, throw in a cabover Kenworth to round things out), and modified almost all of them to some extent, although this will be the first kit car I'll be building.

It's not that I'm super budget conscious (although I did have a price point in mind with this, I always blow past those like everyone else), but everyone's got their criteria for what they want and what they're willing to pay. For me I see where the complete kit offers value, but I don't think that for me the extra cost would be worth it. I’m not interested in doing a $50k build with all new Coyote crate motor etc.

With that said, time to start looking for parts. :D

[Murd]

Congrats on pulling the trigger, I did I very similar build I just got on the road in gelcoat and have a little over 1000 miles on. A blast to drive but I am really going to miss the build come winter!
I used an 88 Mustang donor, which I bought well before the kit and a base kit with almost every option, because of the sale they were having it was still far less than a complete. I stripped the donor of everything the manual said to, which was tough as much of it was very rusted and lots of seized bolts.
Once I started cleaning everything up, as well as doing more research I started abandoning donor parts for new. In the end all I used from that car was the short block with stock rotating assembly, rear end housing and gears and driveshaft.
The T5 was going to cost more to rebuild then I paid for a rebuilt one.
The rear end I swapped axels for 5 luv and a new 31 spline diff, had it sandblasted and painted.
The short block I put new aluminum heads and pretty much everything else and converted to carb.
I did buy some 94-95 spindles on eBay, this was one of the only regrets of my build is that I didn’t get the FFR spindles. I didn’t realize how much better liked the FFR ones are, if I did it again I would have optioned those for sure. As Edwardb states above this one should be a no brainer. I haven’t driven both but will take his word for it.
In the end I don’t regret going the donor route, I parted out what I didn’t need for at least $500 more than I paid for the car, but it had some really good aftermarket parts on it too. If it was stock I would have probably sold nothing.
I basically saved the cost of a 100k mile engine and a rear end and it was a lot of time and hassle.

Couple other notes:
I have 3.73s, it came in my donor car. Obviously very snappy but first gear is absolutely useless, 2nd pretty short too. Given the choice I would do 3.55s.

Other than spindles, I would have ordered the blank dash as I wanted to make a comp dash instead of the street dash it comes with. Made my own but just getting a blank would have been easier.

Not sure if there is any money to be saved but I would get the fan switch and radiator only from FFR. I couldn’t get the supplies SS hoses and adaptors to seal and bought the cooling hoses from breeze, also sold by boig.

By the time I changed everything on my rear end, not too sure how far ahead I was vs just buying one. As others have stated, there isn’t a stock mustang one that is ideal due to fox being 4 lug and drum brake, later being too wide for the nice deep dish backspace wheels.

Good luck!

[TexasAviator]

There are tons of great replies in here so I won't add to the confusion. I did what you are talking about with the mix of fox and sn95 parts to complete the rear axle on a budget. I still got fat 315 wide tires in the rear. I probably have one if the most comprehensive build cost sheets in my build thread. I took part donor part new and built a quality 475hp car for around 23000 using the base kit. This is your build, take it slow and read all you can.

[FlyingCobra]

There are tons of great replies in here so I won't add to the confusion. I did what you are talking about with the mix of fox and sn95 parts to complete the rear axle on a budget. I still got fat 315 wide tires in the rear. I probably have one if the most comprehensive build cost sheets in my build thread. I took part donor part new and built a quality 475hp car for around 23000 using the base kit. This is your build, take it slow and read all you can.

You've got some incredible detail in your build thread, and it looks like your build is very similar to what I'm looking for. One question I've been trying to figure out is whether I should go for a 302 or 347, but have been leaning towards the 347. I do want to stick with the 302 block rather than a 351 block just for the weight savings plus having a smaller block in there that's easier to work around. More to think about.

How do you like the 3.73s? Do you think the gearing is too short?

[Jeff Kleiner]

How do you like the 3.73s? Do you think the gearing is too short?

Let me point out that whether gearing is "too short" depends not only on the rear axle but also which transmission is used. For example the T5 can have either a 3.35:1 or 2.95:1 first gear (similar ratios are available in Tremec TKO, either 3.27 or 2.87 first gear). Do the math; a 3.55 rear end with 3.35 first gear nets an overall reduction of 11.9:1 while a 2.95 first gear combined with a 3.73 rear results in an 11.0:1 overall---in this case the deep reduction first with a higher ratio rear end is actually "shorter". Do the math before making a final decision; and don't forget to look at the other end and also consider what you'll wind up with in 5th gear. Personally, unless dealing with an engine that's kind of soft I like a first gear overall above 10:1 but no greater than about 11:1...my favorite in almost all cases is a 2.95 (2.87 if Tremec) first gear with a 3.55 rear end.

Cheers,
Jeff

[Murd]

From what’s I see all the T5s in Mustangs from 1985 on have 3.35 first gear. I only mention this as the OP is looking for donor cars.
I have this setup with 3.73 rear which gives a 12.5:1 final drive, it’s way too deep to be useful, not sure if the 11.9 with 3.55s would feel much different?

[FlyingCobra]

Good points. I need to spend some time doing math and also thinking about how I plan to build the engine as far as it’s rev range, although I think that’ll work out fine regardless.

[Richard Oben]

Get on craigslist or even better the insurance auctions. Buy an 87 to 93 donor. If you can drive it better deal. My opinion if one puts new bearings and seals on a used spindle is it really used? The rear disc conversion is $800 including hardened axles. The front is rotor swap for $100. Rebuild the 302 with a cam that you like. Just build the car do the hard things to change first. Gears, 3 link, battery box, cam and lower end, control arms. Buy a distributor for an 85 carb mustang run it with an MSD and swap intakes.

Later if desired, swap the heads, spindles for cobra brakes ($500), etc. make it yours slowly. We have a local that followed this plan and spent $30K all done painted and everything. One thing about the donor, all the hardware is there. Buy an engine and a transmission and then what about all the stuff in between?

We built a lot of cars using donors. Some high miles some low. And we have seen a lot of non donor builds and all are more about the builder than the parts used. JMHO, Richard.

[Joel Hauser]

I built an MK4 roadster using the basic kit, and a 1996 mustang GT as a donor. My donor car cost me $2000, which was probably $1999 more than it was worth. In addition to machine work on the block and heads, I had to buy new pistons, bearings, crank, plastic intake manifold and most of the sensors. I purchased a manual rack from factory five, as well as their custom headers. I used the 1996 mustang brakes, but had to buy a different master cylinder because I did not use the power assist parts; the tech folks at FF told me which master cylinder to get, and it worked fine. I bought new stock style front lower control arms because the ball joints were shot. I bought a new gas tank, but only because the lock ring for the fuel pump was bad. I used the mustang wiring harness, which was a real pain, but saved me several hundred dollars. And I used the original mustang wheels because the wider rear end from the 1996 GT was too wide for those super wide wheels you get with the kit. I was going to use the mustang gauges, but they didn't work, so I ended up buying a set from Dolphin. When I added up everything I think I have $26,000 invested in my completed car.
If I had to do it all over again I think I would have gone with the complete kit, and a GOOD donor car. If your donor runs well, you can save yourself a lot of stress, trouble and money in the long run; It took me a better part of a year to get my engine tuned right. But it can be done with a 1996 donor. I have a picture album on the forum if you want to see my car.