Oil pressure problem, Help Please.

hi guys and girls, hoping someone can give me a hand to fix my oil pressure drama, or have had the same problem before. bit of back ground, LA 410 stroker, eagle forged crank ,k1 rods, Indy 360-1 heads, T&D rockers, Crane ultra solid roller lifters, Crower 34701 Camshaft. OK now the problem i just put the new Crower camshaft in, had a howard one in before and crane lifters, howards lifters before them. now i started it up and i only have 20 psi oil pressure. the crower camshaft has a groove all around it for head oiling not just holes like the other cams i've got. And the pushrods are hollow so oil can go up them too. I'm at a loss to know where the pressure has gone, any ideas.