Pontiac sd is right on the money!!

pull the spark plugs, pour about 4 tablespoons (sometimes a little more) of Marvel Mystery Oil into each cylinder. Pull the valve covers and coat the upper end of the rockers, springs valves with oil (it will drain back into the pan). Let sit for a few days (patience is your friend, if you are low on patience it will kick you into your pocket-book). Check the engine oil level and drain a bit if you need too. Try turning the motor over by hand, if its stuck, keep soaking. IMPORTANT: WHILE YOU ARE TURNING THE ENGINE OVER WATCH THE VALVES, MAKE SURE THEY ARE MOVING AND NOT STUCK. NOTHING WORSE THAN CRANKING THE MOTOR OVER WITH A STUCK VALVE, YOU WILL EITHER BEND A PUSH ROD OR WORSE A VALVE. I HAVE DONE THIS BEFORE, AGAIN, I HAD NO PATIENCE! If you want to, start the engine with the valve covers off. It will sling oil all over if everything is working properly but at least you can make sure the upper end is getting good oil pressure (you can clean the engine with Simple Green once everything is sealed back up).