Does anybody know will a 300 top end fit on the 250 bottom end or are they different thanks

 

yes it will but should u?? no, because the ports will not line up but if your pocket book is deep enough, dennis at az bad boyz performance will send u a 12 mm stroker and port the 300 jug to make the ports line up and such but u will be running race fuel, a hpd pipe, aggressive clutch kit, and a new carb, thats like 2500 or more of stuff.