[Cliff R]

My stock HEI has been in 4 different engines since the mid 1980's and never touched it till a few months ago. The mechanical advance mechanism started to stick slightly right off idle, not allowing the timing to fully return to the base setting each time it came back to idle.

I pulled the distributor, removed the shaft, took everything apart, lightly polished a few pieces and put it back together. Didn't take pics of the shaft where it rides in the bushing or the bushing but there was a very slight shiny appearance opposite the camshaft but no visible wear on the shaft. The shaft would move about .002" or so it that direction only, but not enough to worry about and the gear looked to be in near mint condition, which surprised me because it's a bronze gear running on a HR camshaft since 2009.

I've been into a lot of factory HEI's and nearly every single one of them will show a little wear at the shaft, and some scratching/scoring lines from debris in the oil, and a little wear in the direction away from the cam. This simply happens because they use helical cut gears which improve mesh area, but produce thrust up and away from the drive gear. I reject about 30 percent of them these days when the shaft is worn down even though we can put in a new bushing, so I'm constantly stealing shafts from good cores.

Seeing a distributor lower bushing fail in a couple hundred miles tells me it had major issues right out of the box. I'd be hesitant to use it again, considering the cost of an engine vs the cost of replacing it with something better........FWIW.......Cliff