Was wondering if anyone had or has experience with this kit. I know of two companies that make them. If so was cooling a problem, how did they perform. Did you have twin pipes or an aftermarket single? Any help would be appreciated. Also does anyone know what engine toni H. used to win the gold medal in the first snocross X-Games. I know that the second place racer had a 800cc polaris.

bueler....,,,,bueler

670 to 740 makes an awesome engine. made one with a 95 Mach 1. Stock pipes, gutted airbox, 46 mm carbs. 150 horse on pump gas. 180 horse with Jaws race pipes for the grass.

a 740 without porting the case isn't worth the effort IMO. A well prepped 670 will be just as fast and make simular hp. Add a 740 topend to a good case and make a few more hp, but the torque jumps alot. catch the torque (100lbs+) with some good clutching and gearing and they rock. Wiseco has a piston and sleeve to do the job. We ran a pipe off a X. Also heard of using a polaris piston? Precision performance (PPP) has built quite a few and are the first ones I know that were doing it. Might be good to talk to them.