2 fuel pumps, 1 big problem

The 1973 has an electric pump ( have one on mine). I was informed by an old dealer mech that it was added to the system because of a Vaper lock problem that is created by the cooling system connections that go through the carbs. When the car ran for a long time the fule would vaperize in the lines and the car would either stop running or would not start after turning it off.