Right rearend for the job

[CTX-SLPR]

Howdy,

I am expecting to make about 600-650 hp out of my new twin turbo 4.1 but I know the stock 7.5 will just go poof given the chance, what is the right rear end to handle this amount of power and deliver it to the street? The car will spend about 50-60% time on the street so no spools here. I really want to go for a Corvette IRS with a Dana 44 center section but not sure if it will take that kind of pounding. Are my only options, 8.5 10 bolt, 12 bolt/8.8" Ford and 9" Ford?

Thanks,

 

[Rickracer]

Out of the ones you named...

my preference, in order of desireability, would be the 12 bolt, the 8.5, the 8.8, and then the 9". I had a 12 bolt with a factory posi that I rebuilt, and put literally thousands of runs on it. I was running a big block with lots of nitrous towards the end, and never broke it. And there are lots of cars running 10s with 8.5s. 8.8s are plenty stron, but do ya really want Ford parts in yer car? The 9" is easy, but they aren't really that strong without good factory or aftermarket part (both usually very expensive, rare, or both). Just a few aftermarket parts can make any of the above axles nearly bulletproof.

 

[CTX-SLPR]

Howdy,

How much will it cost to find and build each of those rear ends to handle 600-650 hp? I don't need the cost of fabricating brackets but getting brakes that will work with the stock system, or upgraded 4 wheel disc system would be appreciated if you could include that in the cost.

Thanks,

 

[Rickracer]

There are many suppliers for braking systems

I just build rears. I once did do a rear disc system on a 38" wide 9" I built for a SBC front motor dragster though. It was Lincoln Versailles RDB based, and used a hand control. Not exactly what you are looking for, but it did stop the 1350 lb. dragster from 152 mph with no chute.
Baer Brakes : http://www.baer.com/Products/BrakeSystems.aspx
Master Power Brakes : http://www.mpbrakes.com/
Stainless Steel Brakes has a rear disc conversion for the OE 8.5 rear here: http://www.ssbrakes.com/products/detail/2679/?make=Buick&model=Grand+National&year=1987 . I hope this has been of some help to you.

 

[Rickracer]

Here's another worthwhile setup

I found this on MP Brakes : http://www.mpbrakes.com/dr1700k.htm

 

[CTX-SLPR]

Howdy,

Well thats not exactly what I meant by the brake comment. I really meant adapting whatever existing sytem was on the rearend to the car and changing the master cylinder to match. Anyway I'm looking to see how much it would cost to upgrade the rearend from whatever piddly piece I start with to something thats not going to turn into a grenade when the power is layed down. Honestly its looking like it would be cheaper to buy a corvette rear suspetion setup, sell the Dana 36 center section if its not a Dana 44 and buy a reman 44 then upgrade the Ujoints narrow it and stuff it in. Anything but a brandnew, read mega expensive, rear end is going to require simular modifications and fabrication, and probably more upgraded parts. Its honestly easier to narrow the C4 IRS than it is to narrow a 12 bolt/8.8" (no I don't care about having Ford stuff in the back of the car when I have plenty of it up front) or 9" and the stock brakes on the C4 IRS are bigger than the stock fronts on the G-bodies. Anyway, just weighing my options here online. Please chime in if you have a comment.

Thanks,

 

[Rickracer]

What body is it we're building here?

That would help. I haven't really done many Vette IRS units, other than gear replacements, and rebuilding.