9/16" Prop Shaft for KE4, Mark7 and KE7 is Part # 44-22399 smooth shaft
KF7 and KG7 have a 5/8" Prop Shaft 44-24487 with splines for fiber/metal discs clutch
KG4 has Prop Shaft Part # 44-24569 smooth shaft
It is possible to mix parts and create some interesting alternatives. I do not know that there
would be any reason to do so ,but, it is possible to have a KE4 7 1/2 hp with a KF7, KG7 or
KG4 prop shaft and case .or the other way around too ,for that matter.
It can get real creative on the Dark Side.