I just bought a crankenstein (617 rotax mated to a yamaha banshee tranny in a quad frame). My question is a 617 and a 670 motor in the same engine family? Whats the differences? Im wondering if cylinders off a 670 will bolt on the 617 bottom end. I was told the bolt pattern is the same but the transfer tunnels are bigger on the 670? Where can i find information or a manual that is rotax specific. The previous owner said it has about 150 hp on alcohol. Im wanting another 25-35 hp. Where do i start looking for more power?