crf450 engine into 400ex body

[450rracer16]

I do not know if this the right section or not but i am currently thinking about putting a crf450 engine into the 400ex body. I was wondering how bad does it vibrate because ive heard the cr500s will vibrate the bolts loose is the crf450 just as bad?

[hatfield44]

CRF 450 should have less vibration than CR500
CRF 450 = balanced 4 stroke
CR 500 = unbalanced 2 stroke

Got a buddy with a cr500 motor in a z400 frame and it will shake the guts out of you, but it has held together.