[LS short box]

Back in the day my wife's 70 Impala was acting weird. Hard starting. Come to find out the bushings inside the distributor had seized on the shaft. It made the body of the distributor rotate and change the timing. Don't recall if it advanced or retarded the timing. Worth putting in a piston stop and confirming timing marks. Easy to make a piston stop out of a spark plug. Just cut the electrode off and weld a small piece of round stock. Turn the engine over by hand one way and when the piston (#1) comes up against the stop mark the balancer. Then turn it the other way and mark the balancer. Half way between those two marks will be TDC on the balancer.