is it in the car?
Battery is full charge to run starter?
All spark plugs out?
Throttle at WOT and remove air filter?
If those number are accurate the engine have big problems.
Most normal car engines run ~ 110-130 psig dry, a little more wet, and all should be close to same number. Bigger problems as top and bottom numbers get wider and wider.
"Spec" is 14.7(1 Standard Atmosphere) × CR (the compression ratio) = x PSIG IOW 14.7 × 8.5 = 124.95 to give you a target.
(Metric 1 bar or 101KPa × CR = x bar/KPa for testing this depending on gauge used.)
GM allows low number to 80%+ at 200rpm of the highest number but closer is better. Min test pressure is 100psi for all 1982-90 gas engines. (from Alldata.)
If high is 124.95 then 80% is 99.94 and you technically fail testing.
Many other books say 15-20 psi max spread.
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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)The Ogre's Fiero Cave[This message has been edited by theogre (edited 08-21-2018).]
