I haven't torn into the original engine yet, only the spare. It has the older style cam chain adjusters (either all in or all out, no in-between), and both the starter and counter-balance chains have a healthy amount of stretch (again, fixed tensioners for both chains, and both had more than comfortable amounts of play). I'll be looking for the later adjusters that were supposedly externally adjustable for those 2 chains, they're just a bit more rare than everything else.
On paper, these bikes put down a whopping 38-41 WHP and weighed in at 540 wet... I'm hoping to gain performance through judicious use of a cut-off wheel and aluminum, and (if budget allows) updating the CV carbs to a set of VM Mikunis and building a fully custom exhaust. Haven't had any forward progress on finding the later model hi-comp pistons though.