Having trouble with erratic idle , poor acceleration , stumbles.......chances are your bushing in the distributer are wore out on the mechanical advance, no parts are available, I made my new bushings out of bearing bronze, these will last , it's not a job for the average mechanic, you will need a lathe and machining skills to rebuild this, the advance weight bushings are made from fiberglass based material that wears out quickly, the upper part of the weight has a cam follower that rides in a slot, mine was hanging out of the slot, after sizing , machining and installing them, we are back on track,