GilleyK

Have an 86 currently with stock rear and gears. Have a 350 in it. Unsure of hp at the moment. On it's way to being street/strip. Tires, wheels and rear are really the only things left. Looking around for opinions on what to do with my rear end? Just re gear and lock mine or do a swap? Any advice will help and be appreciated. New to all of this so bare with me. Thanks in advance!

big gear head

If the HP will be under 400 and you use an automatic and foot brake then the 7.5 rear end might hold up. I would use the 28 spline Eaton Posi and a set of 28 spline axles. Use quality brand name parts. Be sure that the pinion depth, bearing preload and backlash are set exactly right and consider a T/A Performance cover.

If power will be above 400 HP or you use a trans brake or manual transmission then consider a complete rear end upgrade, like a Moser or Quick Performance 9 inch or 12 bolt.

GilleyK

Alright thank you, I will start by getting it on a dyno and go from there.

AlkyIROC

Even a HP limit isn't an exact science. Street cars have broken the 10 bolt and drag cars have made them survive. Just getting dyno numbers won't guarantee it will survive or not. It's always going to be a dice roll with this tiny ring gear diff.

If you have money to make a high HP engine, you should also be spending money on the rest of the driveline to handle the extra power.

GilleyK

I don't mind spending the money, what I am looking for is what is recommended to use, myself was thinking about building my rear that's on there, axles, diff, gears, locker. But wanted to know if it's worth or go with a completely different rear

big gear head

I agree with what Alky said. If you have the money then don't spend any of it on the 7.5, just start off with something stronger. Most people who post the same question that you did either don't have the money or don't want to spend it on the rear end, which is why I gave the answer that I did.