New motor - low/no oil pressure - help!

Hi Guys,

Just fired up the new 5.0 today (fired first crank, first go) and I seem to have a problem. No oil is coming up to the top end of the motor, and the oil pressure is pretty low.

If you tap the throttle a little (up to say 1500rpm) a few times I can get 10 ish PSI (20w50 breakin oil). If you let it sit idling its lower than that. There is something wrong but I don't know where to start looking.

Background:
- Brand new 5.0 roller block, TFS cam & heads
- new melling std volume oil pump and rod
- MSD distributor with steel gear
- 20w50 penzoil breakin oil

Priming:
Oil pump was primed to some extent with a drill prior to releasing smoke spirits from the drill (i.e. it was not up to the load). I did accidentally run it clockwise for a while before I worked out I should be going the other way. Oil was seen to be flowing through the dizzy hole but no oil came from the rockers. Rockers were oiled manually assuming that cranking the engine would lead to joy. Engine was cranked for up to 1 or 2 min and showed 5psi while doing so with the plugs out.

Engine was started and run for maybe 3mins (with lots of starting and stoping) in total with no oil coming out of the rocker gear. We did hear one smallish clunk but noone was sure what it was. Seemed to run pretty well considering the guessed timing.

Ideas so far:
- something wrong with the oil pump? Pressure relieve valve maybe?
- oil pump shaft?
- something wrong with the oil filter or the fitting it screws onto
- something else??

99% sure I found the problem. Dug through all my photos of the build up and looked at the good ole ford manual. Found that the factory short block was missing a oil gallery plug at the top of the block directly under the manifold. Consequently all the top end oil was flowing straight into the valley and back down into the sump.

What do you think the chances are of bearing damage in these circumstances? I will be cutting open the oil filter today and will likely drain the oil to check as well just to make sure things are ok.

Good news - Cut the oil filter apart and there was no sign of any metal at all. A little bit of dirt or garbage but nothing metallic looking at all.

The new plug has gone in, intake is back on and it will be fired up again in an hour or so hopefully.