My 1/2 inch return line is in the same location in as the stock pick up was in the stock sending unit, we replace the 5/16 line with 1/2 inch stainless bent to empty into the bottom of the stock A body gas tank away from the sump that the #10 AN is in for the pick up to the pump and filter. I'm sure that you can install or have a 1/2 inch hard line installed in the stock unit or use a #8 AN bulkhead fitting and make a #8 AN soft or hard line work as the pick up. I wouldn't take a chance on using the stock pick up either, even if it is a 3/8 to start with. I have added a second pick up in the stock sending units to meet class rules in the past, I added a 3/8 pickup to the stock 5/16 and used a Y fitting to the pump from both pick ups, that work fine for a long time