From what I can recall Jack Inwood used a Hasselblad Medium format camera in the early days of his Motorsport photography. The negative size was much larger than a 35mm camera therefore the clarity was excellent - but you only got 12 frames on a film. The later years he used a Nikon 35mm camera, but he had stepped back a bit from the motorsport stuff by then.
All his circuit racing negatives have been scanned by the McLaren Trust and are available for purchase in digital or print format I'm told. Unfortunately they haven't got his rally photos at this stage - perhaps they may turn up one day.
He took some great stuff of early NZ rallying especially at night using multiple flash setups. He also setup a sign on the road before the corner he was on telling drivers to smile as they were about to be flashed!