For a lot of years, my "test stand" was a forklift pallet, a truck tire, and a garden hose. I've run all sorts of engines that way, and discovered some pretty serious problems that we fixed before going to the effort of installing them. At the very least, you should have pulled some sheet metal- - - -valve cover, and possibly the oil pan- - - to get a reading on the general condition of things. With a battery, a compression gauge, and an air hose, you could have discovered the leaky/stuck valve(s). Before going to the effort of pulling the head, I'd suggest doing a leakdown test of the cylinders with working valves to check on the condition of the piston rings. Putting a freshly reconditioned head on an engine with worn or broken rings won't be a good idea- - - -better to know the condition of the bottom end of the engine- - - -rings and also connecting rod bearings- - - -before trying to do a valve job.
One of the ongoing jokes on Stovebolt is "IRWIPI" "It Ran When I Parked It!" It's possible the engine stopped with that exhaust valve open and it gummed up or rusted to the guide during storage. Quite often, stale gasoline residue from a gas tank that hasn't been used in a while can cause valves to seize in their guides after a short time of running when an "IRWIPI" gets fired up after a long time in storage. Never, ever just add gas to a tank of a vehicle that's been in storage for months or years. Use a clean auxiliary tank and fresh gas. I use an outboard motor fuel tank to wake up a stored vehicle.
Jerry
