Our History

Howell Engine Developments, Inc. was formed in 1988 by Bill and Matt Howell to support the growing trend towards the use of electronic fuel injection in the Hot Rod/Street Rod and Four Wheel Drive Industries. At Howell EFI, we do not make a one size fits all product line. Our customer support team knows every question to ask to make certain that what we ship covers every possible base for a complete and easy to install system. All kits are covered by a money back guarantee.

Our goal is to reduce the difficulty in adapting late model GM engines or fuel injection systems in older pre-computer vehicles of all types. Towards this goal, we offer an extensive line of stand alone and integrated wiring harnesses adapting the late model GM V-8 or 4.3L V-6 engines to any vehicle with simple wiring connecting the harness to battery and ignition power. This makes it possible for individuals with limited electronics experience to utilize the latest in production fuel injected engines in their favorite chassis.

As an adjunct to our wiring harnesses, we developed complete throttle body and multi-port fuel injection systems. We combine proven GM electronic components, Howell wiring harnesses, two and four-barrel TBI and TPI units. These systems offer GM closed-loop fuel and spark control, and typical GM durability and fuel economy.With extensive development on both big-block (454/502 CID) and small block (350/400 CID) engines, these systems are attractive updates for both hot rods, production carbureted vehicles, and off-road four wheel drive vehicles seeking performance and fuel economy.

All Howell systems are full function, utilizing the GM computer (ECM), and Oxygen sensor, and complete GM diagnostic capabilities. When warmed up, engines operate in “Closed Loop” mode with the ECM adjusting air/fuel ratio and spark timing as dictated by the oxygen sensor in the exhaust pipe. This results in good performance, fuel mileage, and durability at all altitudes and in all weather conditions. GM on-board diagnostics continuously monitor the system for proper operation and inform you of any faults via a “Check Engine” light mounted on your dash or other location of your choice.

Our wiring harnesses are constructed using GM Packard high temperature (TXL insulation) automotive wire, genuine Packard connectors and terminals, and Packard crimping tools. With these components, you can expect GM 100,000+ mile durability and function. Our street rod and show quality TPI harnesses are covered with black nylon hose braid for attractive appearance and protection from abrasion. Throttle body and any reworked harnesses are covered with production style slit-nylon corrugated tubing.



Our Guarantee:

We choose to sell only the best quality components, and all are covered by a money back guarantee. We reserve the right to charge a restocking fee on all new parts returned. Our normal parts guarantee is replacement, if they fail within 90 days of service. On used or rebuilt parts such as ECMs, distributors, etc., our guarantee is for 6 months of service.



“Our DUKW’s see a lot of use giving tours throughout the city and even into the St. Charles River. EFI definitely was the way to go. The instructions and labeling of Howell’s product made it simple. Love the product. The fuel mileage savings alone has more than paid for the product cost.”
Tony Cerulle – Boston Duck Boat Tours

“Hey fellow Gearheadz. When building your machine, it’s all about keepin’ it fun, and makin’ it RUN! Well, if you’re transplanting an injected engine, you’ve got to check out Howell Engine Development. Over the years I have used them on many projects, and their stuff is top-notch. Their integrated wiring harnesses will help you get maximum power, fuel economy, AND they’re easy to install so you don’t end up banging your head against the wall. Hey, they don’t call ’em the EFI experts for nothin’!”
Stacey David’s GearZ – Speed Channel – www.staceydavid.com

“Howell harnesses make EFI simpler than installing a carburetor. After completing four Howell installations, I wouldn’t use anything else. It’s just that easy.”
Pat Brewer, Co-Owner – Thunder Road Rod & Custom

“It couldn’t have been easier. Everything was clearly labeled and there were only four wires to hook up. Everything else was plug and play and it fired up with no problem the first time.”
Rick Gero – Evolution Auto

“I bought my Jeep new right from the showroom floor, and recently spent two years restoring it to original except for installing the Howell EFI kit. It was always hard to start and never ran this well; the new EFI system has made all the difference. It starts, idles, and run a lot better than it ever did. I really like the conversion kit and am glad I installed it.”
Waldo McIntosh, Oklahoma – 1984 Jeep CJ7 Owner