[smallblock450sl]

I find a G2 engine ,at "wide open throttle" (remember...if one of the 2 accelerator cables are bad...you can't get "WOT") and a good battery (to turn the engine over fast enough) you sould have a reading of 165 to 175 lbs compression. At 30 lbs I would almost expect a push rod off one of the rocker arms. (valve adjustment should be 4 thousanths , both intake and exhaust, when the engine is "cold") The old mechanic"s test (no affence to old mechanic"s) is add alittle oil to the cylinder after the first test...if compression increases...bad rings. Be carefull about grounding the spark plug when compression testing...If the spark should "jump/miss"...you could damage the ignitor box that controls the spark. Hope this helps alittle. Let us know what you find...it may help the next guy. Later Dave