My engine was bored .060" over, and there is .050 missing from the bottom of the head, leaving most of the quench trench by the intake valves missing. The machine shop also put in all new valve seats at an unknown level. If the new seats were ground too shallow, compression would be even higher.
I did a hot compression check on all cylinders before I pulled the head, #2 through #6 were at 240 PSI (+/- 5 PSI), and the #1 with the leaky exhaust valve was at 180 PSI.
That is about 100 PSI too high. Its a brand new gauge. I doubt that the gauge is off by 58%.
