That's just a direct drive chassis (judging by the muffler). In any case, the G model uses a planetary gear set in the drive cover and that isn't in picture. I believe the crankshafts are different between the two, but I wouldn't know how to tell.
Don't give up.
Chris B.
I know nothing about these or any wright. But come across them on my searches for other stuff. Thats why I been giving you a heads up on the ones I come across.