There is probably another gallery plug missing somewhere. Perhaps inside the engine, it just runs down into the pan.

Rear main seal,there are some incorrect seals(too short)floating around in some of the rebuild kits lately.

the seals is fine, it's a 1400 bottome end, new pistons, rings, big end, mains, 1200 gx head with new valve seats, valve guides and scemed, new gasket sets (at this stage 3 of them). had engine out 4 times and problem still there. checked bearings, all in the right place and right size

Use an external oil pressure gauge to double-check. Maybe something wrong with the pressure sensor.

Yeah like DD said hook up a external pressure guage, standard light only registers about 5psi below anyway, enough so you know you've basically destroyed your motor, you want about 20psi at idle and about 10psi for every 1k revs after that.
Might need to prime the pump, I know aiden on here had that issue and had to fill the pump with vasoline first to allow it to start pumping. You should have oil pressure before the engine fires, pull the coil wire and crank it over.

someone told me that it might be the oil pickup thats got a crack in it.

Might be a lot of things.

just a quick update. it was the oil pump, i just primed it and everything going. thanks for all the help