Inject The Unexpected

Are we crazy? After gutting the engine bay on our '65 LeMans, swapping in a 500hp 455, and spending a little time tuning the carb and ignition, we drove it around the block a few times, mostly sideways. Then we ripped the carb and intake back off, disabling the car for nearly a month. Why? Because we wanted to install electronic fuel injection. Why, again? Simply put, we wanted a fuel management system that could handle any future mods we could throw at it. Preferably, we wanted a system that could keep otherwise radical engine goodies totally streetable at idle, part-throttle, and full-throttle—even a turbocharger or a centrifugal blower. And from nearly every such example we've seen, carburetors just don't do this very well.

While Ford and Chevy guys have a nice group of bolt-on EFI kits to choose from, the rest of us don't have it quite that easy. In fact, if you think too hard about all the different functions a good EFI system controls, well, putting together an EFI system from scratch seems almost insurmountable. Not true—we did it ourselves. Starting with a computer and harness from Fuel Air Spark Technology (FAST), we put together a powerful EFI system to feed the big 455 in any mild-to-wild incarnation you could ever dream up, whether that means turbocharging, nitrous, or both. And we learned that while it's challenging to inject an engine that Detroit never fuel-injected, it sure as heck can be done.

Converting to EFI likely means you'll learn more about your engine than you ever thought possible. All the carburetor's mechanical systems that work together to give the correct air/fuel ratio have got to be replicated by the EFI system. There's no bimetal choke spring to richen the mixture when your engine's cold. There's no flat-head screw that adjusts the idle speed, and no accelerator pump, either. All these mechanical tasks are replaced by different computerized “maps” that basically match engine load and rpm to values you've programmed into each graph. Fortunately there's no PhD requirement because the computer is preprogrammed with tunable maps that can start and run nearly any engine. To make tuning adjustments easier, we checked off FAST's wide-band oxygen sensor option. It can accurately sense air/fuel ratios far richer or leaner than 14.7:1, so we know when and just how much to tweak the mixture to get the correct air/fuel ratios dialed in. Even if you're an ace at jet changes, we'll bet $20 that our laptop does it quicker.

Of course, a great computer won't do you any good without great parts, so we needed induction, a high-pressure fuel system, and an array of sensors to get this deal up and running. Since the runners move only air in a multiport EFI system, single-plane intakes don't have fuel-puddling and atomization issues, and they won't kill streetability, which might happen when running a carb. Edelbrock's Pontiac Victor got the nod, and Wilson Manifolds performed its magic to convert the intake for use with EFI. That involved milling holes and welding bungs in the base of each runner to mount the injectors. Wilson also machined trick anodized fuel rails and hard-mounted them to the intake, and we found MSD's robust 38-pound injectors a perfect fit. Wilson even ported the Victor's plenum for streamlined airflow, and supplied its low-profile 1,136-cfm throttle-body to ingest big air into the big mill. MSD sent us the required GM-style coolant-temp and air-temp senders that plug into the FAST harness with trick Weatherpack connectors. MSD's one-bar MAP sensor was also necessary to measure engine load on FAST's speed-density EFI system.

We took an unconventional approach to the fuel system to save weight and achieve a cleaner-looking installation. Classic Tube bent identical factory-pattern 3/8-inch stainless fuel lines and added AN-6 nuts on each end for easy high-pressure connection to Earl's braided stainless flexible lines. Both stainless hard lines were run in parallel, factory-style over the axle, along the passenger-side framerail, and through the front crossmember to exit in the stock location behind the steering box. Running both the feed and return along the same path was pretty tight in certain areas, but the clean, simple results are worth it. At the very rear, the factory gas tank wouldn't cut it—we could have sumped it, but we had the Fuel Safe Company build us a custom sumped fuel cell to fit in the stock location.

While most Car Craft readers could tackle this project, don't expect it to be a weekend job, and don't expect it to come cheap. In fact, we'll wrap up the fuel system in the next installment, and you'll also get the full scoop on what it takes to tune this bad boy and see how it performs.

Click here for part 2--Playing The Fueled

Click here for part 3--Fast EFI Tuning Basics

By Tony Nausieda

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