An Injector Harness is required and Holley offers two. The harness with USCAR/Stock injector connectors will cover most applications that are using the factory injectors. The other harness is for the Bosch and Holley (or Jetronic/Minitimer) injector connector that is commonly used in aftermarket applications for larger injectors. View the image gallery to see images of both types of injectors.
The HEMI's Variable Valve Timing is not supported by the Holley EFI systems at this time. You can run an engine that is equipped with VVT, but the cam timing will revert to the mechanical default. The Holley R&D team is working on an accessory harness that will drive the VVT actuator. However, it is not available at this time. The HEMI's Multi-Displacement System (MDS) was primarily designed for fuel economy purposes and does not need to be connected when switching to a Holley EFI system. NOTE: Not legal for sale or use on pollution controlled vehicles.

Emissions Note:

This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.

CLICK THIS LINK FOR IMPORTANT CARB & EPA EMISSIONS INFORMATION ABOUT THIS PART