Hi I just picked up a '72 GT with about 50k mi that has been sitting indoors for 35 years. I am trying to spin the motor and haven't had any luck. I verified it's in neutral and even put a piece of wood to hold the clutch down. Drained the oil and it looked OK (black but no water). After I pulled all the plugs and put Marvel Mystery oil in the cylinders, I first tried cranking it with a new battery. No luck, solenoid engaged but couldn't spin. Next, tried using the 19mm crank bolt (no fan belt) and a breaker bar, still no luck. Sprayed some PB Blaster in the cylinders. Loosened all of the rocker arms. Still nothing. Removed the starter and distributor and finally, nothing. Is it time to pull the head? I don't mind doing that but everything I see so far is telling me it should be clean inside. Under the rocker cover and around the timing chain look great, no corrosion and everything is wet with oil. I just want to see if I'm missing anything obvious before I dig deeper.