Originally Posted By moparx
residual valves are supposed to be used only if the master cylinder is lower than the caliper or wheel cylinder. think of a hot rod with the master cylinder below the floor boards. this is to prevent drainback into the master cylinder. that is why speedway says to use the 2# for the front and the 10# for the rear. some have said they have used these in systems with the master cylinder on the fire wall, but i believe there may have been other issues with their systems and these valves have just been a band-aid fix.
beer

You Sir are under a gross misunderstanding of the use and reasons to use residual valeves, they are intended to keep a certian residual pressure on the wheel cylinders so the springs don't force the shoes in all the way and make the pistons in the cylinders have to travel a lot more before applying pressure on the brake shoes to the drums scope
You may be correct on the original designs back in the 1920 and 1930 when all the master cylindes where usually under the floor boards on those early cars though, the drain back is a concern confused thumbswork

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)