The Austin Champ had the Rolls Royce engine, I owned one in the 70's. The Gipsy had three different engines, the gasoline engines made by Austin, and also a diesel engine that I think was made by Perkins. The independent suspension in the early models was changed to leaf springs and live axles in the later models. This one has a gasoline engine.
It was difficult to find spares for this vehicle in the UK forty years ago never mind in the US today.