Ok, back to the master cylinder, is it one designed (ports are different) for a disc-disc brake system?

You mentioned the long travel on the pedal---is the pedal ratio goofed up and not pushing the pushrod far enough into the cylinder???

Never have figured out why the people building these pedal systems use such long pedal travel and power brakes. I've just never been a big fan of power brakes on Hot Rods, I'd rather have to push the pedal a bit harder and eliminate one more problem prone component from the system (the booster). A lot of the 7" power boosters barely qualify as "junk" IMO.........