Won't turn over

["Dean" <dht3000@adelphia.net>]

Well I took my BJ8 out for a nice Sunday drive and it ran beautifully. Came
back home for breakfast. Then went back out to start the car and nothing but a
clunk. So I thought I would catch it in gear. No dice the motor is locked up
tight. I removed the spark plugs and jacked it up on one side.Then tried to
turn it over by rotating the rear wheel while in 4th gear. It will not budge.
What could have happened ?  It was idling great before I turned the motor off.

Dean
65 BJ8