Got an OT truck with a 351W. Bone Stock. Truck has been parked for almost a year, but ran great before it was parked. A couple months ago I went to start up the truck and move it, but the starter just went "THUNK". I tried to turn the motor by hand and it didn't move. So I started looking for another shortblock to replace this one. Today I figured I would pull the plugs and soak the cylinders and see if that was the culprit. When I removed the #3 spark plug, a drop of water hit the exhaust manifold. Hmmm. So I look at the plug and it's rusty inside. So I blasted the cylinder with air and it sprayed out some water. First thought...blown head gasket. I soaked the cylinders in PB Blaster, MMO, ATF/Acetone. Gave it about 20 minutes and cranked the engine and it spun. So I soaked it again, gave it another 20 minutes, and it spun free. I cleaned up the plugs and installed them, ran the motor for about 20 minutes. It poured smoke out the tailpipe for about 10 minutes then cleared up. Temp was good, oil pressure good, ran great. So I changed the spark plugs for new ones, changed the oil & filter, added some MMO to the oil, and topped off the transmission & brake fluid. While it was idling I popped the radiator cap to check it's level and the coolant was foamy. Hmmmm. I aired up the tires and took it around the block, came back and got my wallet, then headed to the gas station. Drove about 10 miles and it never got hot. There was no trace of coolant in the oil, no trace of oil in the coolant. I'm wondering if I have a cracked head or a blown gasket? Any ideas? I'm thinking of trying to find some better heads anyway because I have a cam/lifters/pushrods/double roller timing chain/headers/billet hei dizzy/intake/carb all new sitting in boxes but was hoping I could limp this critter along for a while before I dug into the motor to install the new parts. It would make sense to do everything all at once.