80'427

I am working on the 95 LT1 383 6" rods that has no oil to the rocker arms. I have done some investigations and all the galley plugs are installed and after using a manual gauge found it has 55psi plus with a drill turing 600 rpms (1200 engine). So it has plenty of oil pressure so why no oil to the rockers? I know now it has to be a lifter, camshaft, pushrod, or/and rocker problem. The cam is a comp hyd roller with a reduced base circle, the lifters are stock gm roller lifters (original), stock hardened push rods and crane gold 1.6 rockers. Could the reduced base circle be causing the problem? I mean it has basicly no oil to the rockers. This is after 15-20min of running and another 20 min post disassembly lubing with drill. I did prelube it and some oil came out the rocker but it took a LONG time and it was very little, thought is was just my dieing drill. Anyone have a suggestions, cause I am about out of ideas.