No oil pressure at idle

Recently fixed the wiring to my oil pressure switch and was dismayed to find the oil light glowing at idle. I removed the switch and placed a mechanical gauge, and it confirmed. Basically zero oil pressure at idle. Comes up to about 5psi at 1500, and climbs from there. Snapping the throttle got me 40-50 psi.
I changed the oil/filter and it made no difference. (No glitter came out either).

Engine is a overhauled Magnum 360. I hadn't noticed any engine noises that would lead me to believe it had oiling issues. Main and rod bearings replaced and plasti-gauged within specs. Cam bearings were not touched when the lunati roller cam was installed. Oil pump is stock Magnum, I just took it apart to check for scoring on the rotor (looked ok). Summit oil pan and pickup (I didn't use Teflon tape on the pickup threads, was I supposed to?). Stock magnum oil pump drive. Wix 51515 (tall filter) and 10w-30 oil.

Anything I can check before I have to pull the motor?
Why doesn't ANYONE ever bother to check the clearance between the pump gears and case? These gearotor pumps are critical ! You HAVE to check the clearance between the rotor lobes and more so the clearance between the rotors and the pump body cover ! Use you heads people, how is the pump going to build any pressure against the oil if it is easier for it just flow around the parts instead of into the oil galleys and against the pressure gauge? The pump spins half the engine speed so with all those places for oil to bleed off and then add clearance in the pump, what do you expect? The engine doesn't open up more clearance at any time while it speeds up so if you start spinning the pump faster than it stands to reason it will pump more oil and make pressure. Now it only takes a little over 5 PSI to float a bearing and unless you have a very sensitive pressure gauge, you're not going to notice much difference above or below 5 PSI readings. The critical issue is that oil is flowing through the engine parts and since you do see over 20 PSI the oil is obviously flowing. You aren't hearing tappets clatter so there's no issue there. Have a look at a brand new Chevy small block or even an old small block, look at the engine manual specs. Chevy's never listed much over 35 PSI at any RPM and a lot of engines did worse than that. In a properly built race engine, clearances on the crank and rods were usually increased to allow more oil flow to cool the parts. Reason it out the more pressure requires more power to make an puts an added strain on the pump and drive system. The generally accepted rule is to have 10 PSI for every 1000 RPM so if you never spin the engine over 4500 than 45 PSI is fine. Now unless the oil pan is smashed, there won't be a problem with the pickup tube because the strain screen and cover are designed to get the pickup as low as possible in the pan for a reason. There will always be a space for oil to enter the pickup even if the pickup contacts the pan. Even in cases where the pan has been bent and the tube is pushed up, it will still let oil flow in. As far as tape or any sealer on the pickup tube threads, doesn't matter, there isn't going to be enough leakage around the threads to make that kind of difference either. Now with the older small block MOPAR's high oil pressure was a no can do issue because it would blow out the gasket at the filter adaptor plate to the block, unless you were running the angle adapter with the cast housing ! Newer engines run 5W30 in a lot of engines and this oil is always thin so it isn't for making pressure, it's for flowing so don't worry about it. My last comment will be about an old Ford Flathead V8 I rebuilt about 45 years ago. I had to bore out 1 hole for a .020 piston because a broken ring had made a mess of the wall. The rest of the cylinders were fine for a re ring. Flatheads were notorious for cracking blocks and basically were worth putting that much into them. They were so old and hard to find parts for even that long ago, I had to settle for a reman pump and the way those things were designed, wasn't anything a person could do about some of the clearances just like an AMC, Buick, or any other engine with a pump housing cast in the timing cover outside of replacing the cover to tighten up the spaces. The only you could do was to take out end clearance in the cover piece of the pump which is basically all you can do with any pump! Take what you can get where you can get it. Then think back if you're old enough to remember the way things were in the 40's when engines didn't even have a pump to make pressure beyond 15 PSI at the mains and the pans had troughs in them to catch and hold a bit of oil that dripped down from above and when the connecting rod came down and around, a little scooper splashed some oil up into the rod bearing which was about as hard as a piece of soft lead, called Babbit alloy inlays that had to be melted into place and bonded to the rod. Now we all know how easy it is to melt lead so it would be obvious that it would take much heat to trash one of these. Now if you absolutely must have more pressure than pull the engine remove that pan and pump and open it up to check it. Find out what the specs are supposed to be and fix it ! Sand the pump housing and end cover if it is showing wear till you have between .003 to .005 inch between the sides of those gears and the housing pieces and if you have anymore than .006 to .008 between the gear lobes, replace the pump with a new pump and check it before you install it ! Even new pumps can have too much space for oil to leak by. Personally I never cared for using a stock pump in any engine I built, I nearly always went went with a high volume unit if it was available but as I mentioned, AMC's, Buick's and a few others there was no choice. For those I often installed a shimmed bypass system but that never helped for low speeds. Again, high pressure only draws more power and loads down the pump system which costs you some small amount of efficiency. Don't sweat the little things all the time.