[Walt Fricke]

Fred - you don't say what oil you are using.

In my usual contrarian way, I have never bothered with break-in oil. Just put the synthetic 20-50 in there and drove the car. Other than strange issues in a discussion I think you have looked at with a race motor built from disparate parts from here and there, and a GT3 pump, never much of an issue.

So I share the view that 1) 10 psi per 1,000 rpm is adequate, and 2) will you move to a higher viscosity oil once you are satisfied that it is time to move away from your startup oil?

I see the key here to be that your pressure rises with RPM. At least things are trending as they should, and not the baffling rise to a fairly low X, and then not rising more as engine speed increases.

Pulling the sump (luckily your '80 has the plate, although as suggested it can be installed incorrectly and cause problems) might help. Did you pull and reinstall the piston oil squirters? If one was spat out, chances are you'll find it in the oil when you drain the case. Did you install the cam oil line restrictors (yes, I know that probably you put back on what you had, and which worked fine, before the rebuild).

You might want to do the draining first, before removing the left side overpressure relief plug. That passageway connects with the bottom of the case sump, so - unlike the vertical one - when you pull that plug and the piston comes out, I believe you will drain most of the case anyway.

Good luck - all of us who have had puzzling oil pressure issues not solved with something simple are pulling for you.