I need to replace 10 bolt. I want a rear end that will eventually handle 400-450 rwhp. So I don't need to revist this part of the car. I hear alot of talk on 12 bolts and 9" fords. But I do not know if they need modifactions to work in my 2000 z28. i only have a budget of like 750 dollars, I can save up more to do it correctly if that will determine the rear end lasting in long run

I see some chevy truck 12 bolts for like $200 on CL.

 

You can get a Strange 12-bolt that wil be a direct bolt-in. Comes fully assembled, and run in at the factory. You just swap your brakes over. You will need to advise them if you have 3-channel (ABS only) or 4-channel (ABS + traction control) so they can set up the rear sensors correctly.

You can buy a used 12-bolt from a truck, but it will not have the mount for the 4th Gen's torque arm. Fabricating and installing a TA mount, swapping over all the brackets, and mounts, etc. will take a bit of expertise. And the truck 12-bolts are not the same as the passenger car 12-bolts. They don't all have limited slip, they may not have the rear axle ratio you want, may need to be narrowed, may need new axles, etc.

Moser also make a bolt-in 12-bolt, but it requires some assembly, and has a problem with the bolts for the torque arm mount coming loose. BMR for example, will not warranty their torque arm with the Moser.

A 12-bolt should be more than adequate for the HP levels you are looking for, and with the A4. Next step up would be the Strange (Dana) S60 - 30# heavier than the 12-bolt, stronger, sometimes cheaper, slightly less HP loss, requires the drive shaft to be shortened, tweeks to the torque arm.

Last would be the 9-inch - heavy, limited choices for limted slip diff's at higher axle spline counts, driveshaft and clearance issues because of the pinion shaft being offset to one side (not in the center) and 3/4" lower than the 10-bolt/12-bolt. Cumbersome TA mount offsets some of the advantages of the "quick change" feature. Highest HP losses. Can be built to support huge HP, but cost escalates quickly.

 

Thanks. That was very helpful. My goal for the car is have a rear end for 400hp, do a stall, headers, rear end. Any prices on the 12 bolts, I don't think the truck route looks good for me. More of a direct bolt on. I assume those are more expensive. I'm gunna do some searching for some used ones maybe. Thanks again

 

You're going to spend at least $2,500 for a 12-bolt or an S60. Less if you dropped the ABS. Install is simple enough to do yourself. I have an online install guide.