I ran a combination of a 30 ci block, 35 crank, stock length arc rods and aftermarket flattop gx200 pistons a few years ago. Great little horsepower engine. like Gui said, you have to bore the small end of the rod to fit the new wristpins. Won a indoor race with it after I blew my bigger engine in practice laps. The key is the aftermarket flat top pistons. True honda pistons are dished.