Hi all!! Had a panic stop sat. night going about 50 mph,the back brakes seem to lock up and the rear of the car came right around in a 180(facing traffic),miss the car that pulled out(she came over to apologize,did not see me coming)and nobody was behind me. the car is a 32 glass three window(2600lbs)302 ford with a 5 speed,the front brakes are from a 1956 f1 truck all new parts and the rear are 10.5 ford drum brakes. the master cylinder is a 1963 chevy truck dual set up(brake and clutch),tire are bias ply,road was dry but temps were in the 20s.question is would putting a proportioning valve to the rear brakes help slow the rear from locking up?and can it be put on a car with single master cylinder?. the pedal is hard and the car does not pull side to side. thanks Pete