Well Buck, my gut feeling is the one on the right. But then who knows, maybe those transfer port dividers point the flow more efficiently and make more power?? It also appears there is a difference in the exhaust ports, and that perhaps the one on the right has a slightly higher compression ratio. (Hard to tell in the pics....)

Unfortunately, you won't know until you do a back to back comparison. (times 2)

BTW, it's not too tough to change that engine over to a 21cc cylinder if I'm not mistaken...


AV8TOR