One of the most difficult tasks of fuel-injection retrofit is gettingthe excess fuel returned to the fuel tank. A fuel return must beprovided in the fuel-tank sending unit for proper fuel control. Theearly sending units are small in diameter, which makes it difficult tohang on the retrofit fuel pump and wiring. The fuel should return to thebottom of the tank to avoid dangerous static-electricity buildup. Earlytanks didn't have baffles, which can be detrimental to the fuel pump ifit runs dry during hard acceleration or cornering. The smart choice is acustom-built fuel tank.
Every retrofit requires a fuel-return line, which is another concern.Some of the later Corvettes are equipped with one, but unfortunatelyit's only 1/4 inch in diameter. A 5/16-inch return line is necessary ifthe supply line is 3/8 inch. Higher-horsepower applications requirelarger-diameter fuel-supply and return lines. With regard to the fuelline, replacement of the original 3/8-inch supply line is a good ideawhen installing the return line. It's best to use as much steel line aspossible with the fewest fittings to ensure a safe, pressurized fuelsystem.
The fuel-injection pressurized system (at 45 psi) is like amini-flamethrower if a fire starts. The fuel lines and hoses live in ahostile environment most of their lives. When ordering, check all hosesfor fuel compatibility and pressure ratings. Some of the new fittingsand hoses don't require clamps because they are pushed on and havebarbed fittings that grab the hose.
In a previous issue, we discussed the possibilities of a fuel-tankreplacement on Keisler's Project Maximum Overdrive Ram-Jet fuel-injected'65 Corvette. We decided on the Rick's Hot Rod stainless steel tank.
Hector at RHR had the blueprints for the tank and had assembled a few.We discussed our needs with him, and he made our decision easy: RHRwould build the tank.
The fuel tank was fabricated and welded with quality craftsmanship. Bestof all, it fit without any modifications. RHR uses a universalfuel-level sending unit with the OHM resistance necessary for correctfuel-gauge operation. They install an ACDelco fuel pump in acustom-built housing to contain the required wiring and fuel-lineconnections. The tank installation was simple, but plumbing the fuellines and hoses was a bit more difficult.
The RHR fuel tank made the retrofit easier and added a reliable fuelsystem with easily maintained components. RHR incorporated a bafflearound the fuel-pump pickup area to avoid fuel starvation on hardlaunches. The fuel tank is a home run in all respects.
We had the body off because the 3/8-inch fuel-supply line that's routedthrough the frame in the rear had considerable internal rust. Removingthe body is a lot of work, but trying to install an additional 5/16-inchfuel-return line is difficult on the '63-'67 cars. These are realconcerns before starting the installation, so plan accordingly if youare in the process of fuel-injection retrofit.