amclives.com still sells the adapter, it's $329, so you may be better off sourcing a flywheel. https://www.amclives.com/collections...rs-and-related

If your cranks are out of the engines, there are specs to have the crank machined to 72-up size posted somewhere on the web. https://theamcforum.com/forum/bw-vs-...opic90775.html

I don't know if MC still sells the adapter. Hopefully he'll see this post.

Bob
tufcj