you can bolt on the 500 topend and basically go, but i THINK the 400s ran 34mm carbs and the 500 uses 38?
but yes this is a much safer easier cheaper way to go. still dont know if cost would be worth the amount of gained performance.
A forum community dedicated to snowmobile owners and enthusiasts. Come join the discussion about performance, racing, troubleshooting, trails, maintenance, riding tips, modifications, classifieds, gear, and more!