First- - - - -even before doing a compression test, pull the valve cover and do a valve adjustment. A tight valve will mess up a compression test and send you chasing down rabbit holes looking for more serious problems. Try doing a search on this site for "companion cylinder valve adjustment". It's the method I've been using on race engines for 50-something years, and it's very reliable.
Next step after checking compression is a power balance test. With the engine set at a fast idle with a tachometer, 1000 RPM or more, and a vacuum gauge attached to the main vacuum port (not distributor vacuum) disconnect one spark plug wire at a time and record the RPM and vacuum drop. A good cylinder will show a definite drop in both RPM and vacuum while a dead one will show little or no change. A burned intake valve will actually show a rise in RPM with the plug shorted sometimes, due to less dilution of the intake mixture with exhaust gases.
Last item- - - -using an unlit Propane torch with the gas valve open a couple of turns, check all the gaskets in the intake system for vacuum leaks. When you find a leak, the engine should smooth out while it's pulling Propane into the manifold.
Jerry
