Originally Posted by BC59
Elevation factors into manifold vacuum as well.
If compression test was done with engine at operating temp I'd next do a 'wet' compression test or a cylinder leakage test .

For those ‘bolters that don’t know what a wet compression test is, after your initial readings, inject about a teaspoon of oil into the cylinder the repeat the test. Don’t inject more that a teaspoon of you may get false results. If the compression comes up significantly (over 10%) it’s the rings. If no increase, it’s the valves.

Phil
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1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube
Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes
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