Check out this thread,
This is what you need to adapt the FE3 head to the SOHC block
http://www.mx6.com/forums/fe-dohc/19...rted-dohc.html (Finally Some Pics Of My Fe Converted To Dohc...)
realistically though, you wouldnt do it, its far easier to use the FE3 block, and stroke it if you want to using the F2 crank.
There are lots of threads in the DOHC part of the forum explaining whats been tried