Sidney004

I confirmed a Head Gasket leak with exhaust blowing out of the coolant surge tank.
Cyl #1 - 130 psi, normal looking plug
Cyl #2 -120 psi, normal looking plug
Cyl #3 -120 psi, normal looking plug
Cyl #4 - 120 psi, normal looking plug, it looked like a little coolant was coming out of the Cyl when I cranked it.
Cyl #5 - 120 psi, Cyl filled with coolant
Cyl #6- 95 psi, normal looking plug
Cyl #7 - 120 psi, oily plug
Cyl #8 - 125 psi, normal looking plug

I did a few readings after adding motor oil to the cylinders and they bumped up 5 psi. it took about 10 revolutions to get max pressure. After 2-3 revolutions the pressure reading were about 30 psi less. Of course, I'll be replacing both head gaskets and sending the heads off to a machine shop for a valve job, new springs and inspection for cracks and straightness. I presume the breech was in Cyl #5 but is there anything you can make of the numbers. Oil pressure on the gauge came up strongly as I cranked it. I used a Harbor Freight compression tester.

Tom400CFI

Too much variation between the best and worst. 35 lbs. Not good.

I would do a leak down test before proceeding. If your leakage in that test, in cylinder #6 is in the head, proceed. If it's past the rings....time to stroke it!