At hot idle, the oil pressure gauge bounces off 0 and I only get around 10-12 at high RPM. I even went and bought a second mechanical gauge to make sure. However, I have 40 psi hot idle and 100 psi at high RPM at the filter housing (I know, I need to port the relief shroud). I should have WAY more than 0 idle, 12 at anything above 3000 at the head feed location. I inspected the cam journals for wear and they are almost mirror polished still, absolutely no grooves. It appears the head is getting plenty of oil. Lifters are very quiet also, I would expect noise with low oil pressure in the head. Has anyone ever seen anything like this before? It seems that I would have to have a restriction in a gallery (physical blockage or head gasket blocking oil passage) or really bad clearances in the bottom-end bearings to lose so much pressure up top.