Just did that on my boat. I was really surprised that my fuel pickup tubes were made out of 5/16 OD nylon tubing. Yes, the carbs went dry at about 4200 rpms. I Used -8 on the supply screwed into a bung that I welded to the back/bottom of the tank, and used -6 return line to a bung welded in to the top/rear of the tank. Since I was welding on the tank I also added a vent on the top/front with -6 line and a k&N breather. Also switched to an aeromotive bypass regulator. Works great.