Chiphead, you wrote.
. But the first distributor showed signs of deflection on gear and shaft. I wrote it off as misaligned distributor or oil pump.The wear on the new oil pump started to show up as a 1/2 circle on the cam side of the oil pump thrust face. Like the inner edge of the dist gear was deflected into the pump body.
One tooth may be fine, rotate gear 180* and that tooth would be severely gouged. Shaft showed signs of hitting oil pump body on 1/2 side only. Like bang-miss-bang-miss-bang......
George suggested
Maybe* the wrong oilpump is part of the problem?
Tony wrote
The stock distributer, whether it's Chevy or GMC, is free to float around a little
NOT. I think this is where the problem lies.
And now you say.
This dist didn't wobble, but it did fit pretty tight in the block. Dist shaft was 'shined up' after just 2 or 3 minutes runtime.
Cam side bottom of pump body is polished.
http://pic4.picturetrail.com/VOL53/819220/1640560/19290692.jpg Wear is on cam side.
http://pic4.picturetrail.com/VOL53/819220/1640560/19290317.jpg Cam and pump gears will try to push away from each other. Pump bushing should support bottom of dist shaft. The "bang-miss-bang-miss" or wobble is coming from the dist shaft tang. When the tang is parallel with the crank, the flat side is holding the gears close together. When the tang is perpendicular, it will slide away. I think the pump is your problem. Pump bushing may be worn or body is tilting away from cam because body is too small or block is worn and simply isn't supporting pump properly.
From the the start, I think you suspected the pump.
One part of this I'm not sure of. I have a cut-away drawing that shows a washer or spacer of some sort on the top of the pump.
