5/16 stock fuel lines-electric fuel pump

I have brand new 5/16 fuel line ,new sender 5/16 and new tank, will need electric fuel pump for new motor ,sometime in near future, 318 magnum about 300 hp should I change fuel line to put pump in ,or is 5/16 good enough, I will change sender so can get one with a return line fitting on it ,any thoughts on set up , thanks