I thought that I read somewhere that only jl-8 rear-ends had tapered flanges?! Is that correct? or am I just wishing? Reason is that i am removing rear-end from car and the axle tubes are tapered at end? (aftermarket set of flanges installed) Thanks!

Heres a short article from the Camaro Untold Secrets site of W Guinn. Whats the rear end code on the tube? That would help you out greatly.

http://www.camaro-untoldsecrets.com/articles/article_fs.htm

I think all 12 bolts have tapered axle tubes except the HD service package rear with disc brakes. The factory JL8 rear was just a standard 12 bolt rear that they welded on the JL8 brackets and parts. It's most likely a standard 12 bolt rear. What are the codes on it?