I’ve sold several sets of BAM’s to people with unbushed stock blocks.

One of them sent me a little video of him running the priming tool with the manifold off.
He was worried about the flow of oil coming out around the lifter wheel from the EDM oiling to the axle.
It was way less than what I’d seen from similar videos using other lifters.

In the end, the hot oil pressure is fine, and that motor completed drag week this year without issue.