Crankshaft, balance shafts, cams and alternator rotor need to be changed. The rotor has the lugs to create the timing signals for the igniter, and you only want one lug for a 360 engine. The carburettor needles and jets are different, but I think that's to match the different exhaust system.
One advantage you would gain is that the ignition system will be able to perform at much higher RPM's because it is firing half as many times.
