oil pressure new build engine

a dark cloud has decended over me, ive rebuilt a v8,for an mgbgt and have for the past few weeks struggled to start it due to a number of reasons, finishing with a faulty amplifier on the dizzy.the non starting is yet to be resolved
during the "non starting period" its back/mis fired quite specatcularly at times, and more recently when turning the engine over it seems to be squeeking/scratching lightly,i believe this noise is getting progressively louder, this led me to double check if there was oil pressure and flow around the engine, its got a remote oil coooler and filter fitted which were pre primed, and the oil pump was packed with vaseline,new cam lubed with cam lube but when i take a rocker cover off and turn it over there is no discernable oil flow.
when cranking the oil pressure light doesnt go out (but it does flicker/go dimmer?),new sensor fitted should it go out under cranking?
and the oil pressure gauge registers nothing (dont know if it did before) should it register something when cranking?
i took the dizzy out and turned the oil pump over with a flat bar in a drill, and the oil flows nicely through the filter and cooler, but still nothing at the top end of the engine, should i expect to see something here
ive checked the oil level and its good if anything slightly over full
sorry to ramble

Hi again buddy , sorry your still having trouble.

the fact that the light flickers only when cranking is good and you said you had good visable flow at the filter so you have some oil pressure.

My 3.9 and most others from what I have heard on here dont spray oil around the rockers, normally if you take the oil filler cap off it just looks slightly damp in there is all.

If you have been cranking it for hours you could have worn away some of the oil you put on during the build, cetainly not what the cam run in procedure inteneded lol

with all this trouble starting it are you sure your valve timing is right, did you get the igntion timing sorted?