I've been throwing around the idea of buying a 318 or 316 and swapping the onan for a kohler 16 horse. What would be the biggest challenge? I know I'd have trouble with the driveshaft, and the exhaust. Seems like most of the 300 series tractors around here have blown engines, and it's impossible to find a running one for anything under 900$. Even the non running running ones are expensive, 500-700$!