You posted a wanted ad for a B18/20. Have you tried to free up the stuck motor? The place to work from is not the front pulley---remove the starter and use the opening to pry at the flywheel--you get much more leverage there and can work it in both directions. Be generous with ATF squirted into each cylinder - leave the plugs loose--so compression can be relieved but save you from squirted oil in every direction once it comes loose. When you get it to move just a little work it back and forth. When you can make a full revolution reinstall the starter and let it do the work.
I had great success with a Triumph GT6 that had been in a stone garage with a dirt floor for 10 years. It was TOTALLY stuck but came loose and ran with one full day's work. Better than chasing all over the countryside. -- Dave