First off, I have a '90 Firebird 3.1 mpfi. It has a disc/drum combo on it now. I plan on swapping this out w/ a 9 bolt Borg Warner Posi Disc Brake rear-end from, what I believe, is an '87 t/a. My question is, will I need a new Proportioning Valve, or can I use the stock setup? I also plan on swapping the front and back disc setup's w/ Baer Street packages...Front w/ 13", Back w/ 12".
How would my stock Braking equipment hold up to these new additions?

Thanks for the help!!

 

Technically you will need a different prop valve but I'd test the setup with what you have and see how it works first. But make sure those '87 calipers are in good working order first. Those are the "bad" calipers, prone to freezing up and not working. Are you set on getting those brakes? If not, just go to PBRs from a '89-97 system.


Ed