motor swap

a friend of mins has an atc 25or and wants to trade motors. would his motor fit in my 4ooex frame easily? and would my 400 motor fit in his atc frame?

[2qk4u]

why in the hill would you want to do someting like that?

the bigger ? is WHY?????????????

[Juggalo]

i'm guessin cuz the 250r engine is faster than the 400EX engine.

250r motor is faster and i know how to work on a two smoke pretty good.