Posi-Rear end

[Ciacci]

I am in the process of rebuilding a 71 GS 455 and i am looking for a posi rear end to put in. What options are there that will fit. Someone told me that i could use a 12 bolt posi from an iroc or 80's Z28 is this true? Please HELP

[70 gsconvt]

I do not believe that you could use something from that era. You need a Chevelle, GTO/LeMans, 442/Cutlass, ElCamino, or Monte Carlo from 70-72 to bolt right in.

[VandaLL]

I don't know about f-body rears, but I just put a cheb 12-bolt from a 70 monte into my 72 skylark. It bolts right up, but you have to be aware of the u-joint.. since mine is an older rear going into a later car, I needed an offset u-joint (shorter width on the rear part) with the bigger diameter end caps on the driveshaft side. At first we got an offset u-joint for the earlier models with the end caps at about 1/16" smaller diameter.

Randy