Don, Al told me 400 psi when the engine is hot, 10% less for a cold motor and if there is a big drop in one cylinder do a leak down and put some oil in that cylinder for a false seal. My numbers were as follows (2)@310 (3)@320 and (1)@325 so my hole motor is a little weak. I ran into a big issue with the pushrod cover gasket blowing off so now I have a new gasket RTV'd onto a new cover with a 24V vent on the front with a catch can and the 12V one on the rear going to an oil/air separator and it's fine now, I did the compression test cause I thought I might have a bigger issue. Back on the water, don't really know the long term effects of it but I don't use it that much, when I had the head off the motor was real clean, no build up.<br><br>Jim