Smokejumper,
I think the general consensus is where 'varnish' is involved, the only way to solve the problem properly is to remove the head and have it rebuilt. Turning the engine by hand won't always show a problem. The 'varnish' tends to become gummy as the engine warms up and this is when it will freeze a valve.
I would replace any bent pushrod, clean the engine up a bit changing the oil and dealing with any old, stale gasoline and see how it works. I have fiddled with these old rigs for many moons and have personally never encountered the 'varnish monster'.
Stuart
