Better fit crf or trx engine

[trx250r180]

what would be a better fit a crf 450r or trx 450r,i have a leager chassis with cr500 link,the trx seems wider so prob wouldnt need kick extention,plus i like the forward kick better or e start 06,ive seen buch of dirt bike engines in leagers frame but has anyone tried a atv one,do you have better mount clearance at bottom and swingarm pivot?

[quader400]

not sure on all that but the dirtbike engine will give you more power, because they detune the quads 450 and you would have to get a cam and some stuff to get it back up to the dirtbikes hp. my 2 cents