I built a 318 stroker 390. Priming the oil system with drill on low rpm it has 110 lbs oil pressure. Am running 5-30 break in oil. Anyone know how much to cut off spring to lower pressure? All by bearing clearances are .0025.

I would get a new spring ...stock one...before cutting

FYI,
on my 383 with a high volume pump, cold idle was 95 psi. Replaced spring with one from a standard pump, pressure cold was 55 psi

What cup plug was used the hi press spring usually put out about 75.

The stock cup plug is very thin wall, If you use a standard 5/8 cup plug it usually pushes it up to 90.

The pressure will drop down some after break in.

Pull the oil pump bypass valve out and make sure it has a small block valve in it (with several holes in the spring cup part) and not a BB type with no holes
there was a bad batch of new Melling's or the other manufacturer years ago that had the wrong bypass valves in them

Boy, I must have got one of those from Rock Auto, rebuilt a 340, started it on the run stand and it instantly pegged the pressure gauge, blew the seal from the oil filter and ballooned the Wix filter. Glad it was on the run stand and not in the car. It actually ruined my gauge as it would read 20 more PSI than it should have.

I would assume the bypass valve is stuck.