I guess EJ Potters Chevy and the Drag Waye VW would be the most famous car engined bikes,but there were quite a few in the 70s.The Imp engine seemed a popular choice,all alloy ohc 4 cylinder and the scrapyards must have been full of them.Here's a few starting with Moonraker from 66 which featured an English built flat 4 AJB engine.
Anyone know anything about the first bike taken at the 1971 Internationals
the other bike from 1969 427 Ford powered, early shakedown runs 9.7+165