Vapor Lock question

The electric fuel pump can change things especially if you have changed from 5/16" to 3/8" or larger fuel lines. The new 3/8" sender unit on mine has an additional vent line to which I built and attached my own vent system using coiled aluminum hose and an inline fuel filter. The coils keep the fuel from sloshing out. Some add a one way valve so fuel can't get out in case of a rollover. It works great and the fuel flows perfectly.