 A completely new design was commenced in 1970, after which a friend (Don Biggar) persuaded Shead to construct an additional car, Mk4H Hill-climb car powered by an Oldsmobile V8 engine.By 1973 Shead gave up his usual job to design and build race cars full-time.The final car was produced in 1989, being a Mk9 for use in Formula Holden.