most road bike frames are pretty strong, it's the wheels that clydes have to worry about...
at 273lbs and 6 foot, i ride a specialized roubaix (aluminum frame, carbon seatstays and fork). the only problem i've had was with the oem wheelset (they werent strong enough for me and the roads i ride). i replaced them with mavic cxp33's (32 hole) on ultegra hubs. the tires i use are specialized roubaix pros sized at 23/25x700c (they are 25c, but have a 23c tread size) and i run them at ~125psi (the recommended maximum).