funky oil pressure

ok guys here goes... i recently finished building my .030 350 chevy. it sounds great BUT when its warm it has 70 psi, then when it warms up it drops to about 50 . Give it even the slightest touch on the pedal an it jumps back to 70 + psi.. no biggie right.

OK heres the problem........ take the car for a drive and the pressure changes it goes from 60 psi/ 70 psi range to 25psi or less when u got ur foot in it, let off the gas or goose it and it jumps back to when it should be.. the only thing i can think it is would be the HV pump. Because i had my machine shop double check all clearances and tap and plug ALL the oil holes. im running my gauge from the back of the block behind the intake, and all my gauges are NEW auto meter. I've had this happen before on other engines ive built , and i changed the HV pump and the oil filter adapter which always fixed the problem. im just kinda worried it might be something different since its such a fresh engine. Any thoughts? Also i have an ignition problem..... u get on it hardand at about 3600 rpms it starts to studdern an stumble ( acts like the coil to me) but for all i know it could just be the dual points mallory. any help would be great on these problems Thanks

It sounds like a pick-up problem to me, like the pump's sucking all the oil up to the top when you wood it.
The other problem could be a lot of things, dist. curve, valves out of adjustment, timing, I'd put it on a Dyno, and get a complete tune-up before I started snatching parts out though. I have a friend over there that has a mobile Dyno, and I don't think she charges that much. I'll e-mail her & ask if you like. I think she's in Henderson and does all the shows.