I just went and looked at the manual again. It does sat 1400 at a 4' head, however, it also say for maximum flow a 1 1/2" line should be used. The fitting comming off the pump itself is a 3/4" and that is what I've used for the rest of the line. So...I'm not really sure what mine is flowing at. That being said, who really wants a big honkin 1 1/2" pipe in there tank? LOL.
Al.