You no longer have to use the BOP 8.2 rear end. You can use any GM rear, as long as it is the same length as an original 8.2 that came in the car. This makes an aftermarket 12-bolt the obvious choice. A factory 12-bolt can be used, but must use C-clip Eliminators & stronger axles. Moser & other companies sell HD 12-bolt rears that will work great in a '68 Bird Stocker. Better to get ends that don't require the C-clip Elims.
Most all the leaf spring Pontiac Stockers now use the CalTracs type traction bars. I'm sure there are lots of other suspension tricks, including loosening up the front suspension, getting the correct shocks, and other things which allow the Stockers to hook up with only 9" wide slicks.
