If by chance the cam has been changed, the readings can be lower then a stock engine due to valve overlap. Why are you checking the compression? Is the engine worn out and tired? Are you just wondering what it is? With them all them the same, thats a good sign, at least they are all worn the same.
Recheck with a different gauge, engine warm, no spark plugs, good battery, and spin each cylinder atleast four compression strokes. If they are all still the same, you did it right, if they are higher, even better! Joe
