Can't vouch for it, haven't personally used it, but here you go https://www.ebay.com/itm/Bolt-on-Fl...l8AAOSwxZZbdGkN:sc:USPSFirstClass!53186!US!-1
I'm sure there are others. Smart shopping can snag you a good used 318 or early 340 flywheel on the cheap (relatively speaking).
Make sure you address the pilot bearing/crank issue before you put it together.