Jen, so far, all the "new" engines have been adapted to the quick change rear end, with most of the hardware used on the Honda's. The initial cost of adapting one of the newer, production bike engines, is offset by the lack of having to buy aftermarket pistons, rods, cams, and etc, by a bunch, plus the fact that the newer engines are very plentyful, not that the Honda's aren't, but it's the amount necessary to spend to buy the aftermarket racing parts for them. The newer engines, come from the factory, with all the pieces needed, to go racing, they run them harder on the street, than we do in racing them, we've been running one now for almost 5 years, with very little problems, mostly my fault, certainly no engine failures. And, I have an onboard starter, that I can use, sitting on jackstands in the shop, if I want to ck for oil leaks, or anything else. Bob