[mr48chev]

That is the best set of instructions on running a compression test I have seen on the net and the exact way it should be done.

I would expect worn rings and excess blowby that builds pressure in the crankcase but you normally see signs of that with the engine running with the breather cap off and sending smoke signals out the breather cap hole. These engines didn't get huge mileage numbers before needing a rebuild and going much past 60/70 K without a rebuild or valve job was a cause for bragging rights at the coffee club. 100K without a rebuild might have gotten mention in the home town weekly paper back then. You can't expect the miles before needing work that you do now.

The leak down test would be a good thing to perform or have performed if the compression test doesn't show an obvious issue. You don't need a huge compressor to do that. You do want it relatively quiet around the work area so you can hear any leak along with seeing it on the gauge.