It's an early one so the bell housing should be the same depth as a Commer one, but you would need to measure it to be certain. If it isn't then the input shaft would need to be changed which involves stripping the gearbox and replacing the existing gear and bearing on the Commer input with those off the OD box. You would also need a propshaft to match the coarse splines of the OD box and get it shortened. Lastly a clutch plate to fit which ever input shaft you use. Nothing to it