zx14 has stronger box than zx12 but i wished I bought the zx12 head its a better unit than the zx14, flows better and head bolts have a consistent lay out. zx12 head is used on the kawasaki zx15 supercharged jetski 1.5 L 300hp. The zx15 engine is like a car engine check it out very different sep gearbox to crankcase. Vmax motor is awesome but heavy 130kg with box double zx15 & zx12/14 with box. honda v4 1300cc is normal V config Vmax unfortunately sideways but Vmax is the awesome motor in everyway love a vmax trike :)