Another reason that many radiator frames have the top bar disconnected from the radiator frame is so the fame could be mounted backwards and the radiator mounted on the inside would then not touch the long-shaft water pumps on 55-62 235/261 engines (for a quick and easy engine replacement). The top bar from the radiator frame was still needed so that the radiator shroud (and hood latch) had a cross brace, connected to the fenders/etc.
