Did you have the carb throttle propped wide open when you did this? It can make a few #'s difference. #5 may be on its way.... you can get a lot of wear in a '6 bore and get better numbers than that. I had a bore worn over .020" and it was above 100 psi. Buuuut.... it could be a valve burned or rings stuck. See what a teaspoonful of oil in #5 does to change it compression if any; no change with the oil means valves or head gasket or a crack. Then run it a while and use put 1/2 can of Rislone dribbled down the carb while you keep it revved by hand, and pour the rest in the crankcase for a while to see if it will free up the rings and improve the compression. Usually not, but sometimes you get lucky.
