I have a 66 Vailiant my brakes consist of 81 m body spindles and disc brakes. I use a 74 dart master cylinder for manual disc/drum. The rear brakes are speedway brackets, wilwood calipers small piston and ford explorer rotors. The only proportion valve in the system is an adjustable summit one for the rear brakes. The car slows down well enough but the brakes feel squishy. There is no air in the system. The brakes will not hold the car above 2300 rpm.
Where did I go wrong?