Gearbox complete, Triumph Rigid – Technically 1950s onwards

This is a complete gearbox as per fitted to the Triumph pre-unit rigid models. By my research the stampings T264A where used 1950s onwards however I understand it can fit any rigid model. T264 seems to be just prewar and T264A / B seem to be post war. By 1950 the cases had T909 and T910 on them.