4th gen rear end, in 3rd gen
 

i have a 91 camaro z28. i want to upgrade my rear end to a 4th gen manual rear end, so i have 3.42's and im able to put on z06 rims without spacers. i have the factory 3.23 rear end now with drumb brakes. can i put on the 4th gen rear end that has disk brakes, is it a direct bolt up?

the 4th gen rearend is wider then the 3rd. 1.75" per each side for the 98+ cars, and 2" for the 93-97 cars.

It is a direct bolt in. You will have to change your brake proportion valve for the disk brakes to work.