The following pages trace the development of the JAP speedway engine from its inception through its glory years in the 1930s, 1940s and 1950s. The drawings are copies of factory drawings which were on a roll of microfilm found in a Wolverhampton street probably near the Norton works where the remnants of the JAP company had been moved after its London works were closed in 1963. J. A. Prestwich Industries Limited was liquidated in 1964. The text of the embedded pages can be read at an enlargement of 300% or more on a laptop and more easily at 500% with a larger monitor.