There are two good reasons for going through the trouble of installing a gas tank sump. First, by moving the pickup from the center to the rear of the tank floor, straight-line acceleration forces will cause gasoline to rush toward the pickup instead of away from it for interruption-free delivery to the thirsty motor. Second, the amount of fuel carried in the tank can be greatly reduced without fear of running dry. Remember, gasoline weighs between 6 and 7 pounds per gallon, and the low sump and pickup location should allow safe delivery for quarter-mile jaunts with as few as 5 gallons in the tank rather than the half-tank generally regarded as the safe minimum with the stock pickup location. That’s a potential weight savings of nearly 35 pounds in a typical 20-gallon tank. Also, sumping your stock gas tank is a less invasive and more stock-looking alternative to adding a full-race fuel cell.
We rounded up a brand-new gas tank from CARS Inc. and a sump kit from Competition Engineering, then took them to Williams Classic Chassis Works to see how it’s done. Inside of two hours, our ’55 Chevy gas tank was transformed from a street-bound liability into a strip-ready asset.
