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How to Convert Rochester Fuel Injection to EFI on a 1954 Corvette

Not What It Seems: Converting a Rochester FI unit to Modern EFI

Jeremy D. Clough Aug 25, 2015
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With the current popularity of the all-conquering LS-series of engines, it’s easy to forget that there are still plenty of other ways to skin that particular cat. With a little imagination—and fab skills—it’s still possible to get old-ride style with big power and modern electronic fuel injection. Case in point: the ’54 Corvette owned by Street Shop, Inc. Built on a modern, fabricated chassis with a Ford 9-inch rearend and C4 Corvette front suspension, the C1 has an aftermarket body, but with a correct ’54 VIN tag. It is a legit ’54, but one they’re not afraid to play with. And play with it they have. From the American Racing Salt Flat wheels boasting 315-series rubber tucked up under the fenders to the matte-black primer, the car oozes way more hot rod attitude than code-correct bona fides. Under the hood, it boasts an old-school 427 small-block that dyno’d to the tune of 550 hp — not too shabby for a car weighing in not all that much more than a ton.

Not content with a carb for this application, Street Shop’s founder Tray Walden wanted to include fuel injection in the car without resorting to either an LS or a carb-style throttle body. The answer presented itself in unlikely fashion when he came into possession of half of an original Rochester fuelie manifold. Then he got another half. They matched … mostly. With a little creative welding, the two halves became a single unit, which was then modified to accept modern minitimer-style electronic injectors. An aluminum spacer was machined that would hold a FAST throttle body in place of the factory one, and Donald Lee expertly welded up a fuel rail system that includes stainless hard lines that plug directly into the injectors, hiding the common rail in the opening beneath the upper intake plenum and the lower base to which it attaches.

An aftermarket fuel filter was re-machined and mounted to the side of the intake in place of the factory fuel metering system, where the filter’s new, ribbed shape mimics the valve covers and ribbed intake. To let the engine breathe, a length of tube was bent into a shape that, like the rest of the car, will not mislead a trained eye, but does pay homage to the air intake on a factory fuelie.

We came into the project after the initial metalwork, when it was time to wire it all up. Taking a cue from the clean plumbing of the fuel system, we bent smaller tubing into a similar shape to serve as a conduit for the injector wires, which we purchased from FAST as part of their EZ EFI system. As with our ’72 project car Scarlett, which is being built at Street Shop, we terminated all the wires into a single Delphi HES plug for routing through the firewall, and ran them through either braided conduit or heat-resistant fiberglass conduit, which is our weapon of choice for protecting wires under the hood.

With everything crimped, shrunk, sealed, and bolted back in place, this part of the car is happily complete.

1954 Corvette Rochester Fuelie Efi Conversion 2/16

01. This matte-back ’54 roadster being built at Street Shop, Inc., blends classic hot rod styling cues with just enough original style to still be a Corvette. Follow along as we top off the snarling 427 small-block with a reconstructed original fuelie intake converted to modern EFI.

Strapped Intake Valves 3/16

02. Fear not, my NCRS brothers: no correct parts were harmed in this installation. Walden carefully welded up two scrapped intake halves to create a single, functional unit that was then modified for modern injection.

1954 Corvette Fuel Rail 4/16

03. By far the most impressive part of the fab work; the fuel rail was built from scratch by Donald Lee, who expertly welded up the injector seats and the common rail to feed them.

1954 Corvette Fuel Rail Injector 5/16

04. The fuel rail where it meets the injector: clean, well-designed, and well-executed. The machine work involved to create the seat is particularly impressive.

Aluminum Fuel Filter 6/16

05. An aftermarket, aluminum fuel filter was pressed into service. After being re-machined to appear more period correct, it was mounted to the side of the intake where the fuel metering system would typically appear on a fuelie Corvette.

Fast Wiring Harness 7/16

06. As you’ve seen us do once before on our ’72 project car, we started the wiring with this: a fuel injector harness from FAST. While we used their XFI system in our ’72, this car uses the simpler EZ EFI computer.

Injector Wires 8/16

07. We bent up tubing to serve as a conduit for the injector wires, grouping the wiring by pairs of injectors. One set of wires came out of the end of the conduit, while the others came out through an oval hole made in the middle of the conduit. Although we carefully dressed the holes with a fine needle file, we still used heat shrink to protect the wires where they went into the conduit.

Metri Pack Style Terminal 9/16

08. The injectors have a Metri-Pack style terminal, which crimps into place with the standard Packard crimpers. Once we had terminated the wires into the injector connectors, we then pulled the wires back through the conduit, bringing the injectors as close to the conduit as possible to minimize the amount of exposed wire.

Finished Injector Assembly 10/16

09. The finished injector assembly, with the injectors mounted in both the intake and their fuel rail, and the wiring routed through the conduit. Note that the conduit is held in place with a bracket through which the intake mounting bolt passes.

1954 Corvette Map Sensor 11/16

10. There aren’t a lot of good places to locate the MAP sensor, but it’s got to go somewhere. While it’s possible to route a rubber hose from the manifold to a remote sensor, we wanted to keep everything as close as possible, so we located a drilled hole on the bottom of the intake plenum. We used the threaded hole to mount the bracket we fabbed to hold the MAP sensor in place.

Fiberglass Conduit 12/16

11. Since a clean install that won’t be noticed is pretty much always our goal when wiring, we routed the sensor wires through fiberglass conduit and used heat shrink to compress the conduit to keep it from fraying. Where possible, like here with the IAC and TPS, we combined multiple sensor wires into a single length of conduit.

1954 Corvette Ribbed Valve Cover 13/16

12. The top of the ribbed valve cover had to be clearanced to make room for an air tube large enough to feed the big mouth of the FAST throttle body. Note how it was carefully welded up with a concave piece of material.

Air Temperature Sensor 14/16

13. The air tube was drilled for an air temperature sensor, which is just visible inside the tube at the bottom. We welded a clip on the bottom of the tube to hold the wiring for the sensor.

Airbox Tubing 15/16

14. A larger diameter piece of tubing was used to make an airbox that would hold a Spectre conical filter. Note the air sensor: in this photo, the bottom side of the air tube is pointing upwards.

1954 Corvette Engine Compartment 16/16

15. The finished assembly in place in the engine compartment. A little more crimping and wiring, and we’ll be ready to hear the beast rumble to life.

Sources

FAST
Memphis, TN 38118
877-334-8355
http://www.fuelairspark.com
Street Shop, Inc.
Athens, AL 35611
256-233-5809
www.streetshopinc.com

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