I get a clunk in my 66 when I let off the gas. Motor and trans mounts are tight. previous owner thinks pinion needs to be tightened but that is coming from somene who had a 2700 Variable venturi carb on it and brushpainted white rustoleum everywhere. I have noticed that rear spring bushings are shot. I think that might be the cause. The bolts are welded on the ends so removing the springs are going to need a sawzall . Was it common to weld the bushing bolts to prevent theft? anyway I'm not convinced its the pinion. All help and opinions are appreciated!