1972 Starter dilemna

[rclapper]

I have an original 72 C10 LWB 2wd with a 350, 3 speed manual and factory ac with a noisy starter. I had the starter rebuilt but no change, then had a new clutch, pressure plate, flywheel resurfaced and turned the original ring gear over, still no change except now starter engagement is spotty. Removed the starter, had it rechecked, no problem. The starter bolts to the bell housing, 3 bolt pattern and when I crossed the part number it crosses to a 69 Z28 302 starter. There is no starter listed for my application, I've checked everywhere for a replacement. The 'book' replacement version bolts to the block which I have and it does bolt up and appears to be fine, possibly needing a shim but I haven't hooked it up and tried it yet. Anyone heard of such an issue? I've owned many of these trucks but this is a first. This question is long but condensed considerably.