Update
1) definetly not the rod or main bearings. They were perfect and new ones were too! No difference
2) checked
oil pump internal clearance. Rotor to end plate perfect
3) bypassed
oil cooler no difference union between two fittings which bolt to cooler, still using braided limes a d remote filter
4) reset
oil pump Rv spring. About perfect now sucess there
5) pulled gauge fitting and reducer off block. Used mirror to inspect block orfice. Full of
fuking Teflon. Spent three hours digging it out. I have every pick known to man now.
6) installed new gauge with new tubing. Not much difference in pressure fluctuation. One time revving in driveway I let off gas in neutral and the fuking gauge increased in pressure wtf! I have the first engine where spinning the oil pump slower gains pressure.
7). Started raining. Going to hook up gauge at filter housing again and compare to car gauge.
The absolute last thing I can try is bolting filter to block and that is a long shot since shortest filter is 4" adapter is 1/2 and total space is 4.5". Lol
They way I have run the sheet out of it trying to diagnose this would have failed any worn component. It's screams!
No more removing the oil pan there is absolutely nothing more i know to do in there.
Somebody mentioned a Venturi effect near gauge that appears to be the closest thing at this point.