I have a 77 ford hiboy, same thing the motor sat and was frozen, I filled the cylinders with half trans fluid and half with paint thinner and let is sit for a week drained the oil and sprayed p b blaster in the cylinders. then worked the engine back and forth a little bit more each time untill it would tun compleatly over easily then with the plugs still out used the starter, it blew about a handfull or two of rusty chunks out, i have put about 5k on it so far and it runs great and no smoke