I have a very custom 84 phazer project sled that has been slowly modified over the course of 15 years. It has a 98 pro-action suspension from an srx, custom extended tunnel for 121" new seat, new paint job, 97 venture skis w/ plastic skins, and is currently running a 77 air cooled exciter engine. My dad purchased this sled without a motor and all of the modifications are used parts done by us. I am looking for a big liquid cooled twin to put in it. I have heat exchanger from a vintage srx and some running board heat exchangers from a polaris. I could use any combination of these to accomodate for the liquid cooling. I was wondering what would be my engine options. I am a yamaha loyolist, but the best option i could find is a rotax 670. I have a lead on a recked one very cheap, but we are not sure if it will fit since the carbs are crankcase-mounted. I want it to function like stock (closeable hood, etc.). Anyone have any experience with any motors fitting in this chasis? Arctic wildcat 700? Polaris? Yam 600? and has anyone successfully put a 670 rotax in this chasis? Any help would be appreciated.