Setting the input pressure at 100 and getting 80 lbs on the outlet calculates to be 20 % leakage, not good but not horible either Where the pistons at TDC? If not redo them with the pistons at TDC and see what you get I have seen over 6% differences on the same cylinder when leaking them cold by slightlly rocking the crank 1 to 3 degrees either way Another way to verify the sealing on the valves is to pop the top of the valves so they open a little bit under pressure with a soft blow hammer when the air is in the cylinder I've seen a gain on the readings that way also Same thing on a cold leakdown and then retesting it with the motor warmed up If you get it to test better than 12% I would run it until you can get the motor out and check the ringlands to ring side clearances and see if the ring ends show signs of butting