Misfire at cruise, popping/afterfire at 3000RPM

Yes 3/8 line and sending unit upgrade is a good one. One of the first things I did when I went to six pack induction. 5/16 is adequate if everything is working perfectly no kinks no obstructions etc but why? 3/8 goes right through all the holes in the frame . Six pack like volume and not pressure their little finicky if you start putting too much fuel line pressure to them, one 3/8 line helps and your All good. I just run a Carter muscle car pump and it seems golden.