Hi Big Al,
the difference between the sherpa and land rover engine is the timing casing and the position of the injection pump. I rebuilt one in a 1963 IIa lwb, the front cover on the timing casing is a tin plate, basically, and is not sealed against water and dirt where the land rover has an alloy cover and gasket to seal it. The injection pump on the sherpa engine sits higher up on the engine due to the different timing casing which means it fits the standard series engine mounts where a land rover engine requires the o/s engine mount to be modified to clear the injection pump as it's mounted lower down. The sherpa engine uses a different timing belt which can be a bit difficult to locate now but for the rest I used land rover parts.
Hope this helps.
cheers,
Stevie.