There are not that many makes that have the serial number on the seattube and have that distinctive seatstay treatment. Date wise, I'm guessing after 1974 and before 1982, with late 70s being the most probable based on the braze-ons. That it has fender eyelets also should help narrow it down as I don't think many of the racing builders offered frames with eyelets in the late 70s. Lou Deeter, Orlando Fl