a few questions

[Honda TRX250ex]

Would a 250x/350x conversion with the 350x engine bore to 393 10.5:1 compression with shocks and a-arms keep up with a 400ex? What about a 426ex?
And would a 400ex hot cam fit in a 350x engine?

[prepracing]

it would wear out a stock bore 400ex, don't think it would hang with a 426ex. As for the cam fitting I have no idea, BUT i highly doubt it would interchange into a 350x

[Honda TRX250ex]

bump

[Rip_Tear]

The cam wouldn't work, a 300ex or 250x cam might be compatible.

[kc8pnd]

I think I read somewhere that the 300ex and 350x heads are the same except for the oil return?