Originally Posted by LATECH
Some GM masters did not have them. You need to find out if yours has them. Chances are it does...in the rear....but maybe not the front .
That needs some research...as you will want 10 PSI valves in the front an 2 PSI in the rear.
What bore size is the master and does it have a big and small reservoir?
That would be 10 PSI with drum, 2 PSI with disc. The Brake Man - ValveTechI