I've searched, and everyone seems to say to chop up some axles and stuff a Ford 8.8 rear end into your 1st gen., but I was wondering if there were any other options? I'd like to do a TII rear diff, but that seems like it would be lots of fabrication work. I know Granny's sells a bolt-in 8" rear end package, but I hear it adds lots of weight (not that I couldn't use a little weight in the rear of the car).

I'll be making ~400hp and I'd like to run drag radials without snapping axles and blowing differentials left and right. Also, what transmissions do the higher HP guys use?

 

your going to get a considerable amount more weight with a larger rear end to accomodate your project...I would personally suggest a ford 8.8 rear end...

 

Yeah, I'm leaning towards the Granny's kit, but that causes problems with not knowing which driveshaft to get, which transmission to use, etc.

 

Well if you're running a 400HP rotary engine, you'll be using the S4 or S5 5-speed, right?

Custom driveshafts are relatively cheap in the general scheme of things, so just go for the 8.8". I haven't had any problems with mine.

 

TII trans is the way to go.Its an easy swap and they hold 400+ HP all day long.

With 400HP,the extra weight of the 8.8" Ford is not going to be an issue.If you launch with 400HP and drag radials on the stock FB rearend,your car is going to become a 2600lb paperweight in short order........
Better to motor around with a hundred more lbs of unsprung weight than to push around a couple thousand lbs of disabled car!

 

another option would be a guru diff & axels. Check out there website. http://www.gurumotorsports.com/

 

Popular swap here is a Toyota Hilux rear end, maybe a bit harder to find in the US. Relatively easy to convert over as well. Only downside is you'll be going to 5stud on the rear. But that's just an excuse to do bigger brakes and upgrade to 5stud on the front

 

The full float axles are very nice,but Torsen diffs arent known for their drag racing prowess.They tend to break under high shock torque loads.They are very well suited to road racing though.....

 

when i get up in the HP ranges ill be using a mopar 8 3/4 rear. chop one down to width, get custom moser axles and your good to go. doesnt hurt that i have 2 3rd members and housings either (one of the drag guys on here is using that setup in his 9 second fc)

 

I dunno about going with the Guru stuff, it's all very pricey. I'm leaning towards the Granny's kit because it's a direct bolt in, and is relatively cheap at 725 total.

I'm sure I wouldn't mind the extra weight. I'll be lightening the car considerably, so a little extra weight in the rear end is probably going to be a good thing. Plus, with a 3.4:1 rear end ratio, gas mileage could actually end up being decent.

 

just so you know the granny rear ends they sell complete come from the local junk yard and they just weld the rotary brackets to fit on this application but the gears pumpkin ect is not touched so what you are getting is what ever the rear end came with if i was going to this personally i would buy just the shell get some moser axels get and lsd and upgraded brakes and there you go you have exactly what you want. infact im putting a ford 7.5 on mine no as heavy as the 8.8 but as solid and you can put the parts you want to it , like i added and lsd from summitracing and its made by ford racing this was 210 also i added the ring and pinion also ford racing 168 moser axels with studs 255 custom order them with the 4x110 bolt pattern so i can keep my panasports , you can get the brakes from aerospace components or stainless steel brake or even wilwood , i personally order my brakes for the rear end from rotaryshac and this cost 545 and also the rear end i got from robert as well for 300 and there you go , you have your good solid rear end for about 1200 including good brakes that should hold up 400+ no problem.

 

what does the 8.8 weigh? (complete with axles, housing, and 3rd member)

 

i prefer j-lo's over that waif ally mcbeal

 

I believe it was around 50lbs. over stock, which isn't too much, considering.

 

what does the stock rear weigh? im curious as to how much more my mopar rear end weights. its only a half inch smaller (gearwise) than the 8.8.

 

im a bit over 400 hp right now on the stock rear and its not that bad, plus ive got the low end tq of a v8. im going to get an 8.8 from grannys with moser axles, moser gears, disc brakes, and a detroit truetrac complete from them for 1600.