Put a mild built 454 in my boat for the summer while I rebuild my 496 blower motor. After the first hour on the water I lost oil pressure. It has a melling m77hv after I got it home I pulled the dist. And with my priming tool and drill can build almost 50lbs of pressure. Put the dist. Back in and cranked it and it won’t pump any. There is also a lot of play in the pump shaft now. I measured the dist. Shaft length and distance from the pump shaft to the intake mating surface and that’s correct. Wondering if anybody has any insight on what could have gone wrong before I pull the motor. Unfortunately I think the boat is done for the summer after only one trip out.

I looked it all over pretty well and couldn’t seem to spin the cam gear. I’ll look it over tonight tho. Also it still turns the distributor because it still fires and will run. Thanks for the quick reply

It bolts to the pump with one of the housing screws. It’s definitely a real head scratcher

If the oil primer builds 50 psi I would say pump is fine. I would think it would be cam/dist gear related

Engine will still run and the distributor rotor turns so the cam is still together. I might throw a stock distributor in it and see if it will build pressure. At this point I’m just trying to figure out what’s happening because I’m gunna have to pull the motor out and apart to see what all damage came from the loss of oil