Ok I think this car was originally called the Rorstan Mk 1 but later renamed the Stanton and fitted with a flat 8 Porsche engine. Not certain which name you are looking far but either way it's being driven by Bryan Faloon in the 1972 Tasman series.
You have correctly identified the car, and gain the point.
You've provided me with everything I had down in my notes - this image is from 1971 and thus the car was known as the Rorstan-Porsche. I assume the engine came from a Porsche 906 of some sort (2-litres flat-8).
The car competed in the Tasman series definitely, which from 1970 could include F5000 cars, so I reckon it could have taken part in defined F5000 races, if you see what I mean!
