400ex rebuild

[backwoods 400ex]

hi im looking at redoing the motor in my 2006 400ex i ice race and need to keep up with the 450s better lol. First i was thinking of a 10:1 pistion and sparks x1 cam and keep racing in the class im in, i beat them all off the line but the gradually pass me and gain on me and on a 1/4 mile oval there like 25ft ahead at the end of the race i ussually end up 4th out of like 8 all 450s and one ktm 525 i was running 14-37 gearing. Next i was thinking of going to 416 and move up one class which is all most of the same pple that are in the other class it will be against all stock 450s in both classes. Sorry this is so long but thank you

[sixer3]

a 416 @ 11:1 and a stage 2 cam on a 1/4 mile track would definitely do well for you I think. also if you wanted to stay in that class.

a 10 or 11:1 stock bore, with a carb upgrade and that x1 or hotcams stage 1 came is a nice set-up, i've run that personally with the hotcams and its HUGE improvement. was alos using an 05 trx450r carb