his auction is for a pair of drum to disc brake conversion brackets which will convert your 1955 to 57 full size Pontiac to front disc brakes.   This kit will do what others will not; fit inside a stock 14" drum rim.  These pieces are made in the USA, laser cut from 1/4" cold rolled steel for excellent tolerance control.  No machine work whatsoever is required on your spindle; it does not even need to be removed.    This conversion uses the following components:

Modified Sprinter rotors (stock 5 on 5" bolt pattern) 

Full size GM metric calipers and pads 

Some of our customers have used the existing single chamber master cylinder with good effect.  We do not know of any suitable bolt dual master that will fit.