gold wing engines go forever (I still am the OEM owner of a 78) and best of all. Timing belts are available
I broke one 1979 GL1000
It had done 120,000+ but it stripped the teeth off the rear crank pulley. No idea how or why! Popped a couple of skirts off the carb pistons too. Stuffed another engine in, and got Jon and Wingovations to rebuild an ebay set of carbs and all sorted now.
if you want a plastic car with a second hand (but extremely reliable) engine, then the Ace is the one to go for.