Introducing EFI Engine Connector Kits - From Holley EFI. With the latest addition to our ever-expanding Wiring Shop, our goal was to provide you with every engine connector used on the Holley EFI main harnesses. If you are building a custom engine harnesses for your ride, but you do not have the time to hassle with sorting out every connector, pin, seal and tpa, then these kits are for you! Kits are available for most common domestic V8's, such as; LS, Coyote, 2V and 4V Modular, and GEN III HEMI engines.