DO NOT PUT GAS IN THE TANK. Disconnect the original-equipment fuel system and run the engine on an auxiliary tank like one for an outboard motor, etc. Stale gasoline (or residue from evaporated gas) will cause the valve guides to seize up and bend pushrods, etc.

Before trying to do a startup, remove the spark plugs and squirt a couple of tablespoons of oil into each cylinder. The roll the engine over by hand or put the truck in 3rd. gear and gently roll it forward to spread the oil and prevent breaking the piston rings. etc. If the engine is locked up, do whatever is necessary to free it up before forcing anything. Fresh points, spark plugs, plug wires, distributor cap, rotor, etc. is a very good idea.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!