Inject The Unexpected

Before you order the ECU from FAST, you’ll need to know whether you’d like sequential or bank-to-bank injection, and whether you’d like to upgrade to a wide-band O2 sensor. We consulted with FAST engineers and decided the added precision of sequential injection wasn’t worth it, but the more precise tunability of the wide-band O2 sensor was worth the extra bucks. All these programming options are coded into the part number listed on the back of the compact, weather-resistant ECU. And if you end up wanting any of these special options in the future, you can send your ECU back to the company to be reprogrammed. We like knowing that our engine will never “outgrow” its air/fuel management system.

It’s critical to match the fuel-injector flow to your engine’s power output and fuel efficiency. We estimated our maximum injector flow rate by plugging numbers into MSD’s formula: Injector Flow Rate (lb/hr) = (Horsepower x BSFC) / (No. of Injectors x 0.8), using a conservative 0.47 Brake Specific Fuel Consumption (BSFC), and we found that 38 lb/hr injectors would do the job nicely. For a simpler and more accurate way to calculate injector size, consider MSD’s Injector Selector program (available under PN 2000). It confirmed that the 38 lb/hr injectors were ideal to fuel the 455.

The injectors fit perfectly into the bungs after we lightly coated the O-rings with grease. Wilson TIG-welded brackets off the Victor’s plenum so we could bolt up the fuel rails after seating them on the injectors. The final result is jaw-dropping, to say the least.

And check out Wilson’s slick plenum porting job for streamlined airflow to every cylinder.

We were sure we’d have hood clearance issues with the ultra-high-rise Victor intake, but Wilson’s trick 1,136-cfm four-barrel–style throttle-body saved the day. The throttle-body is half the height of the Demon carb, and comparing the old/new intake combo reveals the EFI system is actually shorter than the carbureted induction. As a bonus, Wilson includes an early-GM–style thread-on idle air control motor and throttle-position sensor. FAST will need to know the IAC and TPS specs on your throttle-body in order to accommodate them in the EFI wire harness.

We’d anticipated an EFI swap months ago when we ordered round-port headers from Doug’s Headers. Doug’s installed an O2 sensor bung in each of the header collectors that were pointed inward about 6 inches from the collector flange. FAST EFI uses only one O2 sensor, but we plan to periodically swap the sensor between cylinder banks to make sure the engine is healthy. Keep in mind both narrow-band and wide-band O2 sensors need heat to operate properly, and this sensor placement is adequately close to the exhaust ports for accurate readings.

MSD hooked us up with conventional GM-style sensors for manifold absolute pressure (PN 2311), air inlet temperature (PN 2320), and engine coolant temperature (PN 2310). The single-bar MAP sensor (two and three-bar MAPs are needed only for boosted engines) was mounted and connected to one of the vacuum ports in the throttle-body. We had a 3/8-inch NPT bung welded into the base of an air cleaner, and threaded in the air temperature sensor. FAST recommended we install the coolant temperature sensor somewhere on the intake, so we bought a trick 304 stainless 1/4-to-3/8-inch NPT reducer at an industrial supply store and installed it with Teflon pipe sealant.

Electronic timing control is one of the many high-tech features of a good EFI system, and we were sure happy to hear that our MSD Pro- Billet distributor would work great for triggering the electronics. Such a system requires you to lock out the centrifugal and vacuum-advance mechanisms on your distributor. Fortunately, MSD made it easy—pull off the weights and springs, remove the drive gear, lift up the shaft, take off the advance-limit bushing, and spin the shaft 180 degrees to align the pin (arrows) with the fixed hole. Secure it with a nut, reassemble everything, and you’re done.

The FAST computer requires you to set the distributor 10 degrees more advanced than you’ll run; for example, we’re maxing out advance at 40 degrees, so we set the distributor to 50 degrees BTDC. The 10-degree margin is there to make sure the computer has ample processing time to do these tasks. Once at 50 degrees BTDC, we phased the distributor rotor in line with the No. 1 terminal on the cap. To finish it all up, we cut off the MSD 6AL’s wires leading to the distributor, installed the FAST-supplied connector on the cut ends, and plugged it into the “CRANK” terminal on the ECU wiring harness. The 6AL’s white “Points” wire was connected to an identical white “POINTS” wire on the FAST harness to fire the box.

Keeping your EFI system happy means having a reliable, powerful, noise-free electrical system, and ours was anything but. The slimy and brittle stock wire harness and externally regulated alternator (bottom) were depriving us of amperage, and we feared the points inside the mechanical regulator might introduce “noise” into the system. We procured a custom harness from M&H Electrical Fabricators that’s designed for use with an internally regulated solid-state alternator. Performance Distributors supplied one of its powerful 61A alternators, which plugged right into our M&H harness and utilized factory bracketry. Check out the long, pink wire (arrow) on the M&H harness—we requested that mod to power our 6AL ignition box mounted far away on the core support.

We thought Classic Tube’s AN-fitted stainless lines looked pretty awesome out of the box, and they looked even cooler after we successfully installed ’em without raising the body for clearance. Earl’s was a no-brainer when it came to procuring the braided stainless fuel lines and fittings we needed to finish the plumbing job. We chose premium Perform-O-Flex line because it’s got a tighter allowable bend radius, meaning we can run the lines less obtrusively. Swivel-Seal hose ends were useful, as they swivel even after they’re installed to make those final routing adjustments easier. At the higher line pressure of EFI (40-50 psi versus 5-7 psi for carburetors), the –6 line we ran is plenty capable of feeding 1.5-2 times as powerful an engine as ours.

We enlisted Holley’s sweet black- anodized billet regulator (PN 512-504-5) to dial in pressure from the company’s PN 12-920 fuel pump. To ensure that cool, fresh fuel is always fed to the injectors, the regulator was plumbed after the fuel rails. The regulator also features a port for connecting a pressure gauge to make pressure adjustments a breeze.

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