I've been having trouble starting my port motor after it sets for a while, when I changed my fuel filters I noticed that the port one was only half full ( or half empty ) anyone know what would cause this? I checked the lines and fittings all the way back to the tank and everything was tight and no visable leaks....bad fuel pump maybe?

What motors, 502's? Sounds like a fuel pump.

They are Mark IV 454's, I don't notice any performance difference between the motors. It doesn't seem the fuel can drain down in the filter because both the inlet and outlet are in the top ????

My neighbors has 454'sin his formula that had a very hard time starting after warmed up & he had his filter boxes moved away from the hot engine & seemed to cure his issues.