I think we have to remember that back then you really only had the option of a engine which was used by the car manufacturer, the dealer would have stated cc size and model spec in the advert, if an operator was looking for a commercial vehicle in the adds, he would want to know what engine was fitted, now for the Guy in question there would be a premium to pay for it to be fitted with a Gardner engine especially a eight potter rather than ■■■■■■■■ if it had a fuel thirsty RR fitted that I believe this would put its value at the bottom end in the aftermarket.