Loud “Pop” after priming oil pump

I was very careful with it and didn’t go balls out by any means. But thanks for the good point. I probably knew that last year but forgot.

I popped off the valve covers and inspected the push rods. All looked normal. Then I hooked up a mechanical oil pump and used a regular cordless drill.l to bring he pressure up. It hovered at 50 psi when I was drilling. I then installed the distributor and rotated the engine again. All seemed totally normal as far as the engine revolutions, with good leakage of oil all over the top end, with no crazy sounds, binding etc...

I’ll keep researching and see what else it could have been. I’m assuming it was a lightly stuck valve in compression stroke. I didn’t feel any noticeable resistance.

Thanks for now everyone!