Those "outside exaust pipes" were non-funtional, just decoration. When I was younger, one of the high school boys had a '41 Chev. coupe with the "outside pipes" as well as the eye shades on the headlights. The eye shades had a pocket on top and in the center to capture a plastic marble, ususlly blue or red. The accessories could be ordered from companies like J.C. Whitnes and others.