Logger, firewood vendor and burn wood at the shop and house. Biggest I use, or biggest that's here? Normally use a 460 or 362, but have bigger ones. No idea what engine size on some, have some 2 man saws I think are twin cylinder even. If it counts, we cut trees down with a 8300cc saw, around 300hp and 40 tons. Normally run a 24" bar. Have a 34" I think, use that once in a while.