I would use the 906 heads and have them angle milled to 75cc to help get your compression up.I would be conservative on the cam with your lower compression.Something like 218 @ .050 on the intake side and 224 on the exhaust.I believe their is a voodoo cam close to that with decent lift.Build it for torue and throttle response and you will be much happier.Big lumpy cams sound great but you don't have the supporting cast to make it work.