honda 350x motor WTT (looking for 300ex)

just picked up a 350 x atc with a mystery motor. im looking for a 350 x motor to replace it with. got a few different 2 a stuff to trade. or maybe buy a motor outright. might consider a running 300 ex or 400 ex motor for a swap. but i need everything electrical etc for that. 520-904-4354