rear end torque limits

[Takid455]

Investigating how much a 10 bolt and 12 bolt rear can handle before they fail. no spools as this will be on the street. car is a 78 trans am (3800lbs) with t56 trans. will see occation 1/4 mile happenings, but mostly street and road race.

can a 12 or 10 take 600+ ft/lb of torque?

do i need to go with a dana 60?

will a 12 bolt with 30/31(?) spline axles hold up to the above mentioned application? can a 10 bolt with aftermarket internals take the power or is it better to step up to the 12 bolt?

[big gear head]

The 8.5 that is in your car can be built to handle that. First you need to have the axle tubes welded so that they don't spin in the center casting. The 8.5 has bad plug welds and they break easily. They must be welded with nickel and it needs to be done by someone who knows how to weld cast iron. Then you need to get a 30 spline differential. The Eaton is good for most street/strip use, but the Detroit Locker is better for a car that is drag raced regularly. The Truetrac or Torsen would be better for road racing. A set of 30 spline Moser c clip axles wolud work fine. Have the gears set up correctly and use quality bearings and other parts and it should be good to go.

If you want a 12 bolt then a Moser would be better than an original rear end. They are stronger than the original and can be had with many options. A Dana 60 would be too much. They are heavy and not needed in your case.