65 Plymouth valiant, 340, 904 automatic floor shifter. It has the “ball and trunnion” front joint on the driveshaft. Has anyone had any success in upgrading this type of driveshaft? I would like to keep this transmission as long as I can upgrade the driveshaft. I don’t plan on having big horsepower in this car. Right now the engine is stock with a cam upgrade… “purple shaft” I was told. No idea what that is.