erratic timing on 360

Yeah the interesting thing is I replaced the I-shaft/oil pump shaft (needlessly) long ago troubleshooting this issue, the old one had some peening to the slot but when comparing measurements the new one was the same slot dimensions. Also, this distributor has a pristine shaft so we are dealing with two parts interfacing that are well within spec and have no wear issues. The bushing it rides in was new as well. Maybe the character of the cam is what was making the shaft want to ride up. I don't know, either way the shaft collar on the distributor fixed it. There is still some slop in the interface between the I-shaft slot and distributor tang, but I don't think its worth peening/filing/welding up the tang to get that last bit of stability. This is a daily driver that will never see the track.

As to the numerous comments about the quality of the machine shop, I have no evidence they cheaped out on parts, again this was third party so I had no direct dealings with the shop, but I don't see why they would when a Cloyes set is so inexpensive ($40). I imagine they tossed the tensioner because they are old-school and don't believe in tensioners, as some on this forum would argue they are unnecessary. There is some slop in my chain and evidence of stretching, but this might just be due to the poor quality of even name brand parts these days. I don't have a degree wheel to determine the exact amount, but it seems relatively minor. It has also only been 2k miles since rebuild.

When I rebuilt the front end (prior to entire engine rebuild due to wiped cam lobe on a tired motor) I used a Cloyes double roller, tensioner, the oil slinger and the hole-thru bolt to drip oil via the tab on the tensioner onto the chain. Hopefully the machine shop didn't toss my slinger and special bolt along with the tensioner.