This harness is for fuel injected small block ford engines, such as 5.0L, or 5.8L Windsor powerplants. Plug and play ignition capability with Dual Sync and HyperSpark Distributors, ignition adapter 558-305 is required for applications with a TFI distributor. The 5.0L Ford main harness is pre-terminated with Ford PWM IAC connector, for the OEM PWM - idle air control motor commonly found on late 80's and early 90's engines. Compatible with Holley EFI Dominator, HP, and Terminator X and X Max ECU's