7.4 chevy engine compresion

can anyone tell me what normal average clynder compresion should be? 55psi. just does not seem like enough.all clys are come up about the same with the engine idleing. thanks for any advice steve.

I think you did the compression test wrong. Engine should be at operating temp. Disable the ignition system. Remove Spark plug and screw in Tester. With a wide open throttle, crank the engine with the starter about five revolutions. Record the results from the tester and go to the next cylinder.

Look for eveness between cylinders instead of max PSI although it should be around 100 PSI.

You tested compression with the engine idling? New to me. I’ve always disabled the ignition, removed the plug from the cylinder under test, attach the gauge in the plug hole, open the throttle and crank with the starter. With the engine running I think the intake manifold vacuum would reduce the numbers.

Edit: I see AlphaDriver beat me to it while I was typing.