I have been messing around setting the adjustable rear brake line proportioning valve on my car. It was a 4 drum factory setup and I converted it to manual disc/drum. Carb is a Quick Fuel 750 mechanical secondary. Ill be moving 10-15 mph and slam on the brakes, and every time the motor dies. It will not fire right back up without playing with the gas pedal a bit. Anybody else ever run into this?