i have recently been looking to bore my 400 out but i cant decide 416 or 426 cause i race flattrack and tt and i put a stage 2 hotcam in it which gave it quite a bit of power but i need a little more and i was thinking the 426 would be good but i dont want it 2 overheat or have to get better valves cause i still trail ride just wondering if anybody has had one and liked it or had troubles thanks