This will not be another attempt to convince those committed to carburetion that modern electronic fuel injection is really the way to go. As a CHP reader and a well-informed gearhead, you already know the pros and cons of each approach. Sure, we'll state the advantages of EFI as part of our discussion. But instead of making a case for fuel injection, we want to look at the issues in one particular case. The snags we encountered while installing and dialing-in an Edelbrock Pro-Flo multipoint electronic fuel injection system are common trip-ups. We hope to help you avoid a few of them and demonstrate what a sorted-out install can do on the dyno.
Doin' It Anyway
OK, we can't help but do a little sermonizing. A correctly installed and set-up electronic fuel injection system has a host of benefits over a tried and true carburetor. Chief among them is improved economy. "Even compared to a perfectly tuned carb," says Edelbrock's Terry Abercrombie, "you're still gonna gain 10-12 percent." That's the bottom line, but an EFI system also improves drivability and cold and hot starting, and it won't be fazed by elevation changes. "And after installation is done," Abercrombie added, "Most EFI systems give you less problems. They're self-cleaning and won't easily degrade your tune-up."
So why do so many enthusiasts stick with carburetors? Sure, traditional mixers have been around for more than a century, and the average wrench is comfortable while dealing with them. And there is the cost factor-a carb is still much less expensive than an EFI setup. But Abercrombie expressed his reasoning plainly: "They're afraid of electronics." And before you bristle at the mention of a fear factor, he added, "As we all are. When Edelbrock first told me I was gonna have to deal with this stuff, I said 'Give me a carb any day.'" Now Abercrombie's most likely the guy you'll end up talking to when you call Edelbrock's EFI tech line.
The Basics
Let's cut to the chase-if a vehicle's electrical system isn't working well enough to support a new Pro-Flo system, the high-tech squirter isn't going to work properly. It's a simple truth that many who install any new EFI system into an old Chevy overlook. "The big thing is the charging system," Abercrombie started off. "It was common for pre-'82 to come with 40- to 60-amp alternators. The output of newer vehicles (almost all of which are fuel injected) is 140 amps. The big thing to do with all older vehicles before installing this system is verify that you have a minimum of 60 amps."
Edelbrock's Pro-Flo EFI system...
Edelbrock's Pro-Flo EFI system comes complete and ready to install. There are two big-block systems: PN 3550, which supports up to 625 hp, and PN 3551, which supports up to 450 ponies; both come with a 1,000-cfm throttle body.
We chose the 3550 system for...
We chose the 3550 system for the 502 crate motor residing under the hood of this well-used '63 Biscayne. Although this Rat was given a smaller bumpstick in its previous life, the high-horsepower system still proved to be the correct choice.
Installation continued by...
Installation continued by plugging the wiring harness into the fuel injectors and sensors. This shot shows two of the critical sensors that make the Pro-Flo work: The throttle position sensor (1), and the MAP (manifold absolute pressure) sensor (2).