I have a 71 with headers. The proportioning valves on the brakes is in the stock position ( inside the frame). Yesterday, after driving around town for a couple of miles, the front disc brakes would not release. After massaging the brake pedal with my foot for 10 minutes ( the brake pedal was as hard as stone) The pedal finally loosened way up and almost went to the floor. Then the brake light on the dash came on. I suspect that the proportionig valve became over heated and would not let the front disc brakes release. The car is back in the garage for now. Should I move the proportioning valve? Where to? There is currently about a 1/2 inch clearance between the header and the valve. All components in the brake system are new/ factory rebuilt. I suspect I may need a new valve. Can anyone help me?