rebuild it!
you could propably rebuild that motor for under 500 bucks.
first fill the crankcase with kerosene or deisel fuel and let it sit for a couple days..the get a prybar and try and get the flywheel to turn...you may be able to free that motor up...
it still might knock terribly...but then you through some rediculously thick oil in it to quite it down and sell it for more!
