Thanks for the point. In fact I thought only the original car, the bottom one in the set of photographs, was based on an Amilcar chassis, but the descriptions suggest they all were.
The two later cars, which raced at Indianapolis, had underslung frames - the photos show the car of Eldridge, which was an offset single-seater with nominal space for a riding mechanic. The car in the puzzle, that of Hawkes, was a pure single-seater although the driving position seems offset because it had to allow for the prop-shaft alongside.
Georgano is a bit vague on the subject.
