IMO you would think that the inside of the crank case is different between the two of them. If you look thru the Engine forums ....[link=http://www.rcuniverse.com/forum/m_5226191/mpage_13/key_/tm.htm]Clicky[/link].... you should see some really modded sleeves but i have never seen anyone put a new "port" in a engines sleeve... honestly i wouldn't even bother with it. Im not even going to get into the whole "timing" thing[&:]