250 / 450 interchangable parts???

[emullen]

Does anyone know what if any parts might bolt up to 450F from a  250F?  I have a 04 250F that I want to see if it is possible to replace the frame with a 450F frame so that I can put a K5 motor in it.  the 250 frame has a single downtube right in the way of the exhaust the 450 has 2 downtubes creating a space for the pipe to exit on a K% motor.

thanks

[mxwink509]

Finally,someone making an aluminum frame KX500! They've been doing it for years with the CR's.