The 6.3L I'm planning on putting in my car is being built to hit close to 400hp/tq. Probably not too far over that at most. I'm putting in a T56 behind the motor. I've read so much on people sticking with the factory 10 bolts and beefing them up to handle power.

I've read many stories on how they made it work perfectly up to about 500hp/tq and others that have grenaded them with 300hp/tq on street tires.

The place I just picked up a T56 from offered me a 4th gen 10 bolt with disc brakes. I know how these are about 2 inches wider but I was told that if I use a wheel made for a 4th gen it won't stick out due to the bolt patterns or something. Is this true?

Also, I've read this.. https://www.thirdgen.org/beefinguprear

I would love to build up the 10 bolt and not worry about the brackets and all that stuff fitting but I'm still worried about breaking it. Would it make more sense to find the 12 bolt/9" deal and go from there?

I'm stumped on the rear end. Help!

 

I think for the horsepower you are looking for you are at the edge of what can be considered "safe" for a "maximum effort" 10 bolt.

Having said that, there are many factors to consider with respect to 10 bolt strength. The biggest issue I hear about is the lack of a good installation.

Gears are quite complicated and deserve an exacting amount of precision and patience on the part of the installer. The parts also play a big deal. Getting a Moser aluminum alloy cover is a must. Getting Timkin Bearings, Eaton Posi or Yukon. AAM Ring and Pinion..etc..

Call Tom at Toms Differentials...Very knowledgeable and the best prices around that I have found.

Some links you may be interested in:

My 10 bolt build-Just finished!!!

https://www.thirdgen.org/forums/tran...0-bolt-re.html

ronusmc's 10 bolt build---Very informative


= (10 Bolt upgrade photos)https://www.thirdgen.org/forums/tran...de-photos.html

http://www.chevyhiperformance.com/te..._gear_install/

http://www.highperformancepontiac.co...d/viewall.html


http://www.highperformancepontiac.co...d/viewall.html

 

You can spend the money on the 10 bolt and take a chance that it will hold up, or you can apply that same money to a stronger rear end. I don't think I would take a chance on the 7.5 holding up. If you had an automatic I would feel a little better about it's chances of surviving.

 

As much as it sucks to hear that, those were probably the answers I was looking for. I Don't want to dump ~$1,000 on a 10-bolt for it to grenade.

Any tips on where to find a used 12-bolt/9" that would fit without much modification?

 

The best way to go is to order one from Moser or Strange. The 9 inch isn't too hard to modify to fit the 3rd gen, but a 12 bolt is much more difficult. Sometimes you can find a used one for sale. You can get a 9 inch housing and axle package from Moser, Strange or QP for around $1000 and put in a junk yard chunk and brakes. If you get it built with the correct housing ends and axle hang out you can use GM brakes on it. The correct Moser housing ends for GM brakes are 7900 for drums and 7900FM for disc.