ok guys im puting a Ft500 motor onto a 400ex frame i know little about the FT500s but i know they are almost the same as the 400 motors but what i want to learn is will the head/cam work off a 400ex or will any parts off a XL/XR fix because i race atvs and 400 motor just doesnt have the power im looking for and does anyone know where to get any part to beef up this motor like a bore kit bigger cam?