restoring 1987 holaday Rambler

I am going to have a 1/2 inch NPT fitting put in the bottom of the tank. A flek line from that to a Holley red pump running a 100 micro filter pre filter. This will be mounted as close to the tank and as low as possible. My old shop teacher once said pumps don't suck, they push. Not sure if I am going to have to run new line at this point but it would not hurt while I a down there.. I have looked and 3/8th copper line is the same as the hard line already there. Gas or most fuels I know of wont harm copper line.
I believe I can push the fuel 25 feet to the carb much better then sucking the fuel around 15 feet,then pushing it another 10 feet or so to another fuel pump thats pushing it then around four feet to the carb