ceslaw Chuck I don't know where you are at, but if you go to
www.percisionmeasure.com they sell a valve seat vacuum tester. It checks vacuum on valve seats and other tests. It also tells about what to look for. I still go with a bad valve guide or seal. They sell a
oil dye for the motor to check for externial
oil leaks, you could use this to check and see if the
oil is being pulled through valves or stem seals or if the gasket for the intake is sucking. You need to pull the head for this tester. Rick L.