Hy panman, as far as I know all dual circuit master cylinders for Corvette applications are for disc/disc applications, that would mean no residual pressure valves in the master cylinder. As has been stated by Wrenchbender Ret. the original master cylinder had a residual pressure valve built into it, and most if not all master cylinders for drum brake applications have them built in. For your own safety and that of those around you on the road, I repectfully sugest that going cheap on brake components is not a wise idea.
