From the Street Rod rules: "Original windshields (convertables), roofs, doors, fenders, grills, hoods, trunks and main body parts must be used (No chopping up, stretching, piecing together or hacking the body). No drilling out or cutting holes in the back of the car. Tail lights need to be attached."
Looks to me like they were referring to a convertible? I read that to mean that you couldn't build a convertible and omit the original windshield to streamline it.