Reply to "electric fuelpumps don't stop"

One thing that can cause a pump to run more than necessary is a slightly leaking float needle valve, and with a Holley, there are two- one on each end. There are various ways to reseat a leaking needle, but most owners simply replace the assembly in their carb.
In the POCA Newsletter of August '09 I described a simple and cheap way (with photos) to add a factory (Ford or GM) TBI (throttle-body injection) in-tank electric fuel pump to an early Pantera. While I don't know for sure that a Longchamp has a large enough fuel gauge sender hole in the tank top, I assume DeTomaso used very similar parts in the Longchamp and DEauville. An in-tank pump is sound-insulated by the volume of fuel in the tank and is virtually silent in operation. Note these factory TBI pumps operate at 15 psi so a fuel pressure regulator will be needed to drop pressure to the 6-7 psi that a carb uses. Being a factory pump, they are cheap, dependable and available anywhere in the world that Ford or GMs are sold, as well as breaker-yards, swap meets and the like. And as I found, their only known weak spot is the inability to be run dry for very long.