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Howell EFI Introduces GEN III Vortec 8.1L Chevy Vortec Engine Swap Wiring Harnesses

8.1 Vortec Harness

Available with Drive by Cable and Allison Transmission Options

Marine City, MI, (June 1, 2023) – Improve air-to-fuel flow and fuel efficiency with a Chevy 8.1L Vortec engine swap.  Howell EFI, an expert manufacturer of EFI systems and components for 35 years, is answering the call for a complete wiring harness for 8.1L Chevy Vortec, (#HVL81) Big Block engine swaps that is plug and play. With symmetrical cathedral port cylinder heads and modern coil near plug ignition much like an LS engine, this engine is a popular choice for truck engine swaps for big torque, lower maintenance, reliability, and improved fuel economy.

The new GEN III Vortec 8.1L wiring harness (1999-2004) can be used for electronic or manual 4L80E or Allison transmissions with emission connections if needed. For a fully mechanical throttle body action, Howell also offers a wiring harness for drive by cable with all the appropriate ECM reprogramming. Both harnesses are covered with high-temperature split loom covering and include all components to make a lower maintenance engine swap a worry-free installation. Made in the USA, Howell’s GEN III harness operates with all stock sensors, the MAF sensor, and the stock ECM and eliminates extra oxygen sensors and emission controls if not required. Reprogramming of the existing ECM or ECM module supplied by Howell is required. ECMs are reprogrammed to the vehicle’s engine and transmission specifications, i.e. gear ratios, tire size, cam changes, vehicle anti-theft (VAT’s) removal, etc. 

Howell EFI President Matt Howell, says, “We are getting more and more calls for 8.1L Vortec wiring harnesses. We are always making an effort to stay ahead of the curve, so we have everything stocked and ready to ship now. There’s no waiting and we are here to help you from your initial inquiry on what is needed for your swap.” 

Howell EFI also offers a 1996-2011 4.3L Vortec harness for the 4L60E/4:80E transmission, a 1996-2001 5.7L Vortec for manual or electronic transmissions, and a 1996-2001 7.4L Vortec for the 4L80E transmission. All EFI wiring harnesses are sold with complete instructions and a money-back guarantee and every sale is supported by Howell’s expert customer service department. Visit here for a copy of the installation instructions for the GEN III Vortec Truck EFI wiring harness. 

For additional information about Howell EFI Vortec wiring harness options, visit, or call 810-765-5100. For the latest in Howell EFI promotions, and company and product news, follow Howell EFI on Facebook, Instagram, or YouTube