Melling M295HV. Also ported it. My oil pressure was fine and, as far as my research showed, the M295HV was the direct replacement for the pump used in the AFM engines, which used a high volume pump. There's no need to try to peg out the oil pressure gauge. It's just excess load on the engine and stress on the seals. ~40psi +/- 25% is fine.
That is the part number for GM "LS7" lifters and what I bought a year ago with GM lifter trays for $123. They're now $260 for just the lifters. If your buddy has some for a good price, SCORE.
I don't know where BT sources his lifters trays from, but I'd imagine he wouldn't hinge his reputation on sub-par items to save a buck when the legit GM ones are (or were?) relatively cheap to begin with.
That is the part number for the GM LS2 timing chain. I bought one on ebay but I'm not sure it's the LS2 one or even GM. I may be taking a gamble.
Last I knew, Melling supplied GM with oil pumps.
I tapped and plugged and have a non-DOD cover (12598832- LS3?) with the gasket that has O-rings to seal off each tower. I've heard of some of those O-ring gaskets leaking a little, causing a pressure drop. This may be on aged engines or something, but the cost to tap and plug was about $5 and it's a guaranteed seal. I already had the cover cuz I ordered all these parts over a year ago. At that time, I wasn't planning on tapping and plugging. If you're not pulling the engine, you're gonna have to block off the tower oil galley through the lifter bore when tapping to keep the shavings out of the engine. I used a donut magnet and had the engine sideways, used lots of thick grease on the tap and used 155 psi through a high volume blow gun to blow the galley clean from the inside-out. Had I not pulled the engine, I probably would've slid some cylindrical magnets hot-glued to a wooden dowel into the lifter bore to catch the tap shavings. Or I would've bought some of the special rivets and borrowed the Lingenfelter rivet tool from a buddy.
Pics and details of the oil pump porting, timing chain comparison and tower tapping are within the last few pages here.