Threads are trashed. Dunno on the head conversion. The R65 is a shorter stoke motor so you would keep the short barrels and push rods. Rockers should be the same but the rocker mounts might not fit. Really don't know. I would only consider R65 heads. If you're interested in the racing ones I have, read over the ad first. I can't see videos. Sorry. If the heads are coming off, just plan on fixing it.