Turn over means it will spin. You mean it turns over but won't start I think .
"Needs a head" I think you mean needs a new topend (cylinder kit/piston)
Ya you may need to take apart the topend and check for "race" damage to piston, do a compression test, leak down test to check for air leaks, head gasket leaks,
Your "race" ignition Hpi may have just died so check for spark. Wow that bike is rough for the street/cop magnet. You may have to put a lot stock things back/rebuild to stock specs.