The Holley Avenger EFI system comes with everything you need, short of some fuel lines/hos
Have you noticed, as you peruse the rows of classic cars at a show, that with a quick glance under the hood, you’ll usually find some sort of production or aftermarket EFI system on top of the engine? Yeah, me too. It seems like an epidemic of sorts. People are jumping on the EFI bandwagon for one reason or another. Some of the upgrades can certainly be chalked up to the wow factor, especially if it’s a trick stack injection system or multi-port setup. But we’d hazard a guess that the majority of the converts are simply tired of dealing with fussy carburetors that leak, smell up the garage, don’t run well, return poor fuel economy, and create hard starting after sitting more than a week (which is typical for our vintage cars).
For those of you still running a carburetor I’m sure you’re shaking your head in agreement at that last string of statements. I’ve experienced them myself on several occasions. So what’s stopping you from upgrading to fuel injection? Yes, the cost is a bit steeper than just bolting on a carburetor, but there’s more to an EFI system than just a cast-aluminum fuel distribution assembly. There’s wiring, electronic controls, sensors, a fuel pump, filters, and more hard parts that contribute to that initial cost. So, you’re getting quite a bit of hardware for your entry fee. Maybe you’re hesitant to install fuel injection because you fear the install itself. You’ve seen factory EFI setups and they look confusing with their modern long-runner manifolds and sensors all over the place. Whatever the reason, you need to open your eyes and wrap your mind around the new throttle-body-based EFI systems coming to market today. They’re compact, easy to install, and cost less than many systems found just a few years ago. Best of all, they use a wide-band oxygen sensor and sophisticated programming that allows the EFI system to learn all on its own while you drive; effectively tuning itself as you go down the road.
One of the newest bolt-on EFI systems to come to market is the Holley kit. Yes, Holley, the brand that has brought enthusiasts carburetors for more than 100 years. Holley has actually been involved in EFI product creation for well over a decade, and some of the company’s new hardware is based loosely on its previous throttle body (TBI) and port-injected manifold kits. However, it’s been fitted with a robust ECU controlling the system that makes it plug-and-play simple to get you up and running.
 Here is our test mule. This ’66 Mustang convertible is used for weekend transportation
Holley has several systems and performance levels in its new EFI lineup. We start with the Avenger line for street and strip use. This is a self-tuning system with a small handheld controller for setup and manual tuning needs. The Avenger is available in two- and four-injector TBI configurations to universally mount on most any Ford intake manifold.
Next, we have the HP systems, which have the ability to be laptop tuned, or tuned via an optional 5.7-inch, full-color touchscreen. The HP is a good choice for big-blocks, high horsepower strokers, and other engines making 400 or more horsepower.
The top dog in Holley’s EFI lineup is its Dominator EFI system, which is designed to be built one part at a time for a custom EFI solution for racing, power adders, electronic trans control, and even data logging. In this article, we’re going to concentrate on the street-friendly Avenger system for the stock 289ci V-8 installation here.
The Avenger 2-V TBI system (PN 550-200) is the starting point in the Avenger lineup, and is good for engines up to 275 hp. That may sound like a limiting factor, but let’s be honest. If you have a stock 289 or 302 and you’re just looking for the benefits of EFI, why pay for more than you’ll need right?
 As we mentioned in the opening text, the 289 is stock, save for a Mallory ignition sys
 To get under way, the air cleaner is removed and the old 2100 two-barrel gets the heav
 Due to the stock Ford iron intake manifold’s 2-V pattern, the Holley adapter plate is
Due to the stock Ford iron intake manifold’s 2-V pattern, the Holley adapter plate is not
 The modified mounting plate is then bolted down to the intake (counter sink screws rep
 You can see here that the stock Mustang mechanical throttle linkage works well with th
 Since we’ll be using an electric fuel pump for delivery to the TBI, the stock fuel pum
 The Avenger’s ECU can be installed under the hood, but be sure to keep it away from di
The Avenger’s ECU can be installed under the hood, but be sure to keep it away from direct
 There are two sensors external to the TBI that will require installation. The inlet ai
 The air temp sensor is nothing more than a bulb-type sensor and a pigtail of wire wit
 The EFI system uses a manifold absolute pressure (MAP) sensor to determine engine loa
 Since we’ll be testing a 4-V Avenger as well, we didn’t get too carried away with mak
 For a return line, a length of steel line was routed under the car and back to the re
 While at the rear of the Mustang we also went ahead and finished mounting the fuel sy
This was the perfect system for our subject’s ’66 Mustang convertible. The 289ci V-8 was dolled up with a chrome air cleaner and valve covers, but performance wise it was sporting nothing more than an upgraded distributor and ignition coil. It was stock right down to the iron exhaust manifolds, iron intake manifold, and Autolite 2100 2-V carburetor. The owner was tired of the extended cranking and pedal pumping to get the car going after sitting more than five days. Not to mention it has had four different rebuilt carburetors on the engine in the last few years just trying to get one decent enough to go down the road. Finally, there was the dismal 14.7 mpg he was getting. We felt this was the perfect opportunity to see how well the Avenger system lived up to its sales brochure claims. Check it out in the photos that follow.
 Another thing to scratch off the under-car work is the installation of the wide-band
 The Avenger wiring harness is mostly a plug and go affair, with just a few loose wire
 The wiring was then carefully routed to the fender and connected to the ECU. The loos
 Finally, the handheld control unit wiring was routed from the glovebox out to the ECU
 The finished installation is very low key and doesn’t shout “I’m EFI!” to those who p
|Autolite 2-V Carburetor||Avenger 2-V TBI Fuel Injection|
As mentioned before, this ’66 Mustang got just 14.7 mpg using a 60-mile test run on AFM’s Dynojet dyno. After setting up the EFI and answering the basic yes/no questions on the controller, the Mustang started right up on the first try and after a minute settled into a perfect 750-rpm idle. Some cruising at different throttle positions and different gear selections were performed, and then the Mustang was strapped back down to AFM’s dyno for another fuel economy test. This time the Mustang’s 60-mile testdrive netted 20.8 mpg and this was at 12.6 to 13.2 AFR. Furthermore, we had AFM dyno test the Mustang before and after the EFI conversion just to see if the 289 might improve in the horsepower department and we weren’t disappointed here either, with a gain of nearly 30 rwhp. At wide open throttle, the carb registered 10:1 AFR, while the more accurate EFI was making more power while using less fuel with its indicated 12:2-12:6 AFR.
 Impressed with the fuel economy and per-formance improvements of the 2-V TBI Avenger,
 The Holley Avenger 4-V TBI system bolts directly to the intake without the need for a
 Just like the 2-V TBI setup, the 4-V unit tucks neatly under the air cleaner for a cl