What rear end size?

I have an 89 Caprice with a 305 tbi th2004r and a 10 bolt with 2.73 open. My question is what size is the 10 bolt? 8.5 or 7.5? How do I find out?

I have an 89 Caprice with a 305 tbi th2004r and a 10 bolt with 2.73 open. My question is what size is the 10 bolt? 8.5 or 7.5? How do I find out?

It'll be a 7.5. The 8.5s in the Caprice were a part of the 9C1 Police Package.

Thanks for the info.

Is it the same thing on an four door '84 Caprice w/ a 305 4BBL and a TH 700-r4 transmission? Also, how many splines would my '84 (or any Caprice for that matter) have? Thanks in Advance!