I just broke a bunch of teeth off the ring and pinion in the stock rear of my 85 IROCZ while accelerating hard. My setup is a Chevy 383 with a T-56 trans I run stock size street tires and do not plan to drag race or run slicks. It is definitely a 400+ hp car.

I was looking for some opinions on if it was worth building up the stock rear or if I should just go to a 12 bolt?

Also I was going about 40-50 mph when the rear broke and I forced the car a short distance back to my garage. My friend mentioned that the cast iron center section may have been damaged by this and should not be rebuilt. Is that possible?

 

Sort of, but not likely. I've seen em where the driver's side carrier bearing had eaten into the housing and the housing wasn't even straight there... you could put bearings in that housing EVERY DAY and TWICE on Sundays just for good measure, and it would STILL whine and vibe.

Tearing up the gears by itself doesn't cause that though.

Best to tear it down and look at it, go from there. Might be possible to just put new gears in it. (prolly not, but ya never know til ya look)

 

Another 7.5 rear end is probably just going to break again. I think you would be better off just investing in a stronger rear end. A 12 bolt, S60 or 9 inch would be a good choice. Moser, Strange, Quick Performance and some others offer good bolt in rear ends.

 

Beefing up a ten bolt with new parts is not cheap so you might want to spend the extra money on one of the suggested rear ends.
But if not here's what I did with my 10 bolt =


https://www.thirdgen.org/forums/tran...de-photos.html

 

Quite so; if all you want to do is just repair it, that's one thing, but to "beef it up", requires a certain level of commitment. At which point, the costs start getting kinda close to replacing it altogether with a MUCH stronger unit.

But as always, don't "assume" anything. LOOK. See what's actually going on before jumping to conclusions.

 

You can slap together another 10 bolt just to get you back on the road but don't expect it to last. If you need something strong enough to handle the extra power, an aftermarket upgrade is required.

High HP is a package deal. You've done the engine and transmission. Now you need to do the differential.