Boat has twin 454 / 330's. I just replaced the cams, lifters, valve springs, intake manifold & ported the cylinder heads. On the maiden voyage today one motor ran fine but one lost all oil pressure during the first WOT run which lasted about 15 seconds. I put a gauge on it and it has no oil pressure. Pulled out the distributor & spun the oil pump rod with a screw driver. It seems to spin ok. Cut open the oil filter & didn't find anything abnormal. Anybody got any ideas,help, or suggestions ? THANKS !

Bo

Putting aside the possibilty of the oil pump being bad, there are many other things that can cause this problem.
You said that you spun the oil pump with a screw driver, did you feel any resistance, or did it turn real free? Do you have access to an engine primer ( the type that you can turn the oil pump with a drill) ? If so, use it and see if you get pressure, that would eliminate any alignment issues with the distributor. If you are satisfied that the pump is not the problem and there is no issues with the bottom end, such as oil clearances, that would leave you with what you added new as a possible culprit. You may have a bad lifter. Can you pull the covers and make sure that all the pushrods are still in the lifters?

I had that trouble with a truck I had. After much wailing and gnashing of teeth, I found the oil pickup screen was clogged. I couldn't believe how small the screen was.

There is a good chance the pickup has fallen off the pump.

The oil pump has resistance and feels like it's working. I looked at the push rods & lifters thru the distributor hole with a mirror and a bend a lite and the push rods all appear to on the lifters. I bent some push rods on this motor on the first start up because the timing chain was not installed properly. Could this have done any thing to cause no oil pressure? It's starting to look like this Checkmate isn't gonna see any water on the 4th.

Bo

I'm with Marc, sounds like the pickup may have come off.