I'm using the same tree and oil pump I had w/o any issues. Tolerances are dead-on to within .05mm of shop manual specs. The best machining equipment made was used on my block. They build NHRA dragsters and speed boats engines mostly, then drag even w/o break-in's. Oil pressure gauge is the same as prior to build, when all pressures were normal. I think my "hybrid turbos are causing huge back pressure and stressing the whole engine??? My freind has high oil pressure on his after rebuild as well from SZ. Can't figure it out. He did a PCV bypass though.