5.3 LS Oil Pressure: How much is " Enough" ?
 

2004 Tahoe flex-fuel, 95,000 miles, bought a year ago with internal coolant leak. Replaced heads, with some cheap-O Mexican Reman (709) from the local CarQuest.
Had some hideously nasty black tarry sludge in bottom of oil pan, used a RISLONE motor flush once, Transmission fluid added before another oil change, and have a total of 6 oil and filter changes over the last 3 months... And a TSP 212/218 camshaft. Runs great.
Indicated oil pressure tends down to the range 28-30 at full operating temp, while cruising at 1500 rpm.

Cold oil pressure will go up to indicated 65 at 3500 rpm.
.
Running down the highway at speed with barely 35 psi, am I in danger of grenading the motor ??
.
.
. ( Note: reference wife's vehicle, not the supercharged Mini-Motor in sig-line)

Sounds fine, maybe a tad low but not horrible.

NNBS trucks are like 50-55 cold and running down the freeway at full operating temp my truck is only at 38-40 psi. The sierra I had with 258k miles was 55-60 cold and 40-45 just driving around and 30-35 at idle warm. As long as the oil pressure jumps you to 50-60 at full throttle it should be alright.

If anything you could buy a new stock oil pump and see what happens.

It's a touch low but I don't think I would bother unless you are dipping to closer to single digits at idle. If it was that much of a mess the oil pump likely isn't the cause of the pressure loss in the first place lol. The new trucks with active fuel management have a stupid little pressure relief valve in the oil pan so getting over 55 psi is nearly impossible with it relieving around there.

2002 with 168k Been through the wringer a few times, and procharged for ~10k

Your pressure sounds identical to mine, and I've never worried. Not yet anyway

My oil pressure has always been around 40 psi. 203K miles. Replaced the oil pump at 168K when I did headers, cam, intake, etc. Never made any change in PSI and the old pump actually looked new. I dont think an exact oil pressure is as important as the actual flow of the oil.

Throw a manual gauge on it before you spend any money on anything.

I have a 4.8 L, for comparison, Always runs 40 plus PSI, at HOT Idle, goes straight up to 65 psi cruising, and holds 70 PSI from 3000rpm and up/.

I have 40 psi at idler and 60+ at 2500 rpms
Gm TSB says at operating temp at idle 35-40. At 2500 rpms at operating temp should be 55-65. At 4500 70-80psi

GM on these Gen 3 and early Gen 4 LS motors they have an orange or green pick up tube seal that is bolted to the oil pump with a 10mm that goes into the pan to suck up oil.

Well those seals fail. They do have an update for them (red) seal now, but if you worries about oil pressure, the seal is 6 bucks at GM and you gotta drop the oil pan. Just a price of oil filter and 3 gaskets it's a cheap piece of mind.

Also keep in mind that the weight of the oil also affects pressure.