Cast iron will offer up a challenge when the engine is 'locked-up'. The method I have used and have had good results starts at the flywheel/teeth. Select that big ugly screw driver with the damaged tip as the pry bar. Insert the tip into a tooth, pry against the block. This is a 'baby-step' procdure. Work on the opposite side. Two of the pistons will be at near top dead center. The other four will be the pistons that will challenge you. If you have any luck with freeing the engine, remove the diesel fuel fron the crankcase / cylinders. Introduce 12 volts to the starter with the plugs out. The freed engine will turn giving you some signs of other problems with-in. This five second test will give you great info on what the future of the engine will be. Put some oil in the engine, clean and set the points, plugs and spray some starting fluid into the carb . . . fire that mother up ! Good luck.
