In the good old days when from Gravity feed Fuel Tanks shifted from the front Bulk Head to under the boot or in the boot, it necessitated the requirment to pump fuel from the rear of the automobile to the front to feed the carburattor. Since electric fuel pumps came in much later, some of them had Auto Vac's, that worked from the Vaccuum of the Inlet Manifold of the engine and some had mechanical fuel pumps that operated, mounted on the engine its self.  This one is of an AUTOVAC Re-build.