Car pulls to left when braking

Check your front strut rod bushings. If they go bad they can cause the front end to pull one way or the other no matter what the brakes are doing. I had bad ones on my old 67 Cuda and it drove me nuts till I replaced them with Moog parts. You probably also know the 9" brakes are worthless. They only sort of slow down the car. You ought to at least upgrade to 10" drums.