So you saw 50 psi on the oil gauge? You just made Uncle Tony jealous.
You should take the valve cover off and see if you have good oil flow up there. If it's sludged up, take the rocker shaft off and clean out the rocker arm oil feed holes in the shaft as they're only about 1/8" diameter.
First thing I think of when a revved up engine squeaks is belts. Take off the belts, rev the engine and see if it still aqueaks.