I think the same one that works for Chevy will work for Pontiac. So, there should be quite a few cheap ones out there.

I made mine. Used a Pontiac HEI housing, and a Chevy HEI shaft.

Takes a nice strong 1/2" drill to turn it fast. Had a good one, but it quit going counterclockwise. Bought a cheap one from Harbor Freight. It works, but just barely. Thought it might burn up, but it didn't. Got the job done.

Here's a couple of name brand models. Should be lots of cheaper Chinese made models out there, especially on Ebay.

https://www.summitracing.com/parts/mor-62200/overview/

https://www.amazon.com/Moroso-62200-Pump-Primer-Chevy/dp/B000COU27K

https://www.summitracing.com/parts/mrg-3795g/overview/make/pontiac

Here's a no name on Ebay, for $15.99 shipped. As usual, Ebay links don't work on THIS site. They work on every other forum & FB page I use. Anybody know why they won't work on this particular site ???

https://www.ebay.com/itm/Oil-Pump-Primer-SBC-Chevy-V8-OIL-PRIMER-TOOL-FREE-SHIPPING-IMCA-USMTS-UMP-DRAG/223439007840?hash=item340600b060:g:kLcAAOSw-1ZcgTXD