Weiand Nostalgia Blower Drive Swingarm End View. NOTE - This type of idler pulley requires a flanged top drive pulley. Weiand made 2 variations of idler pulley though the cover was the same. See drag racing pix at this site for an example. I believe my nostalgia blower drive to be an earlier example based on the idler pulley design. A change of idler pulley will make mine match exactly as per film.