What is a good master cylinder to run with 4 wheel manual disc brakes. I am putting together a rear disc setup for the Dana 60 Im putting together right now. I am using GM metric calipers and using 1980's Diplomat front disc brakes. I also ordered a adjustable propotioning valve. I was running stock rear drums and the Diplomat disc up front with a 94 Dodge Ram aluminum master cylinder but the issue I have now is the peddle is very hard. The brakes work ok but it takes both feet to stop it from 125 mph. The Ram master has a really big piston and is actually a power brake master. I was thinking I needed a manual brake master with a smaller piston. I would like to stay with the aluminum master if possible.