any kind of yz400f or wr motor in ex ? or a 440x motor?

[speedfoxracing]

i want 2 either put a yz400 or 426 or a wr400 wr450 and if i do that it will be a rocket compared 2 doing my motor 2 a 440. wut do u all think i should do cause i,m goin 2 do eith one idk yet

[Duke Nukem]

I have seen the YZ426F done before, that engine makes upper 30's for power stock so you could easily modify it to get 40 some hp. As far as the conversion goes, I would be careful where you put the engine. It's a possibility to lose that good front to back balance that it has for jumping and wheelies. And also some good advice is, when you fabricate those engine mounts weld or bolt them up good for no vibration.