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How to Install an EFI-Ready Fuel System in an Early Chevelle

Baffled: Holley’s new Sniper EFI tanks makes adding EFI to your classic Chevy easier than ever

Tommy Lee Byrd Sep 1, 2017
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The automotive aftermarket has come a long way in helping car guys bring 50-plus-year-old cars into the modern era. Of course, you can engineer the “old car” feeling out of your old Chevy by swapping in an LS engine, overdrive transmission, and updating the suspension. That is not our intention with this 1964 Chevelle four door project car. We want to retain the old-school flavor and simplicity of the original 283ci small-block engine, but we also want it to perform better and get better fuel economy. Part of the process is the installation of a Holley Sniper EFI system, but before we get carried away with the new fuel-injection system we need to bring our entire fuel system up to speed.

For this, we once again called upon Holley for one of its EFI-ready fuel tanks. Holley makes direct fit tanks for many applications, including our 1964 Chevelle. The tank features dual drop-in assemblies for both the fuel sender and the electric fuel pump. We could’ve opted to keep our stock tank and use an inline electric pump, but the convenience and longevity of an in-tank pump made it an easy decision. We’ve also found external pumps to be noisy, and having the pump in the tank keeps it cooler.

It’s important to note that the Holley Sniper EFI-ready fuel tank is applicable for all types of fuel-injection systems, including LS engine swaps. The installation does require some customization of the fuel sender and pump assembly so it’s definitely a good idea to reserve a full weekend of shop time to get it wrapped up. We’re pleased with the fit, finish, and quality of the Holley EFI-ready fuel tank and we’re itching to get the Sniper EFI installed so we can see what this 283 can do with a high-tech fuel system in place of the old Rochester two-barrel carburetor. For now, take a look at the necessary steps to install the new fuel system in a 1964 to 1967 Chevelle and follow along as we start bringing this early A-body into the modern era.

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1. Although nice for its age, this 1964 Chevelle is ready for a new fuel tank. With plans to make the swap to a Holley Sniper EFI system, it was a great time to upgrade to an EFI-ready tank. It’s a good idea to spray some penetrating oil on the tank strap fasteners and give the threads a quick scrub with a wire brush. Then, it’s simply a matter of supporting the tank with a 2x4 and a floor jack, while loosening the nuts and lowering the straps.

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2. Fuel tank removal and installation is usually a two-man job, especially if there is fuel in the tank. The tricky part is rolling forward to clear the filler neck, while at the same time lowering the jack and keeping things steady. After the tank is lowered, we can remove the original fuel hoses as well as the sending unit wire and ground wire. The new Holley tank system comes with new straps so we can also get our crusty straps out of the way.

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3. The new 24-gallon Sniper tank (PN 19-105) from Holley may look stock, but it’s internally baffled with a 4.3-liter internal fuel tray for EFI and it’s an inch deeper for fuel pump clearance, which also adds a bit more capacity. The steel tank is galvanized and then the exterior is powdercoated silver, so it’s a tank that’s going to last a long time and look good doing it.

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4. The new Holley EFI-ready fuel tank comes with a universal sender (0-90 ohms) and fuel pump assembly. We start by disassembling the generic fuel sender in order to shorten it to the appropriate length.

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5. For the 1964-’67 Chevelle tank we’re looking at a depth of 6 1/2 inches so we cut that number in half and added 1/8-inch for gasket thickness. This positions the float arm pivot point at half of the tank’s depth. The lower portion of the two-piece fuel sender bracket can be removed.

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6. Now we can remove the temporary rod and install the float arm. Slide the arm until it rests against the stop and is about 1/8-inch from the mounting surface. Tighten the float arm retaining screw and cut off the excess arm past the stop. At this point you may also trim the excess material from the bottom of the float bracket assembly.

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7. After all of the retaining screws are tight and the wiring connection is tightened on the terminal you can drop the fuel sender into the Holley EFI-ready fuel tank. Be sure to align the rubber gasket and apply a small amount of Indian Head gasket compound for a good seal.

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8. Now it’s time to move to the second drop-in unit: the fuel pump assembly. The beauty of this Holley kit is the in-tank Walbro 255 liter per hour (lph) fuel pump. It’s quiet, it’s reliable, and it can support up to 550 hp at 60 psi (13.5 volts / 10.4 amp draw). The first step is to measure the depth of the tank again and make notes of the fuel pump length.

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9. After careful measurements we can trim several inches off of the black supply line and then trim the white return line so that it is 1 inch from the bottom of the fuel pump assembly. Since the pump and filter sock measure 4.25 inches, we’re looking at shortening the supply line to 2.25 inches and the return line to 5.5 inches.

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10. We heat the black supply line so that it will stretch around the fuel pump fitting. Don’t forget to have your clamps already hanging on the line because once the line shrinks, as it cools, it is difficult to remove.

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11. With the supply line warmed, we can push the fuel pump into place and rotate it around until it is nestled up against the white return line.

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12. After the fuel pump is in place, we slide the supplied sleeve over the pump and keep everything together with the supplied cable ties.

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13. We can now tighten all three clamps on the fuel pump assembly and plug in the pre-installed wires into the fuel pump.

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14. The fuel pump assembly is now ready to drop in to the 2.25-inch hole. It’s important that the fuel pump assembly is oriented so that the supply and return line fittings point toward the front of the car and that the filter sock is aligned with the reservoir tray (toward the rear of the car). After applying a small amount of Indian Head gasket compound to the rubber gasket we tighten the six retaining bolts.

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15. It’s a good idea to use pipe sealant on the fuel pump fittings. The fitting size is 1/4-inch NPT, but we have found it beneficial to use an adapter down to 1/8-inch NPT, as the adapter swells a little more as it’s tightened and offers a better seal.

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16. Holley suggests the use of 3/8-inch fuel injection hose for its Sniper EFI kit. The hoses are routed along the inside of the framerail. A great tip is to mark one of the hoses with a white marker every couple of feet, so that you can differentiate the supply hose from the return hose when making your connections at the engine and tank.

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17. After cutting the wire to length, we crimped a ring terminal on the end of it and heated up some shrink tubing to seal it from the elements. We also made new ground wires for the pump assembly and fuel sender.

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18. Holley sent along these fuel injection clamps, which offer a firm grasp on the 3/8-inch hoses. Fuel leaks are no fun, so we’re sure to double check all of our connections while they are accessible. Also notice the two additional hoses—they are the vent hoses and join with a Y-coupler.

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19. We fabricated a small bracket for the Holley-supplied vent and made sure to mount it above the plane of the filler neck. This allows for adequate ventilation, which is important with a fuel-injection system using an in-tank pump.

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20. Once again, the fuel tank installation process works better with two people, but if you’re attempting it alone, you can use jack stands to provide a couple of extra hands. We installed the supplied rubber hose and filler neck before raising the tank into place.

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21. Whether you’re using this tank in conjunction with a Holley Sniper EFI kit or simply upgrading from a stock tank and inline electric fuel pump, this EFI-ready tank is an excellent way to provide adequate fuel supply. It also works well for LS engine swaps, but it is a perfect fit for our Sniper-equipped 283 stocker.

Photography By Tommy Lee Byrd

Sources

Holley Performance Products
Bowling Green, KY 42101
866-464-6553
http://www.holley.com

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