Moroso Performance Products Mechanical Spark Advance Kit, 1957-75 GM Non HEI Distributors

Do not overlook that little bronze bushing install. You have to dismantle the distributor which isn't too complicated, just follow the directions. In my case, I have a 68 vette. The plastic bushing that this was suppose to replace was completely gone! Without that bushing, properly installed, the counterweights do not swing properly, which effects your advance timing.