Throttle Body Sub Harness: This harness supports all the throttle bodies compatible with the Holley system. The stock 03+ GMT800 throttle body is an 8 Pin throttle body, and uses the 8-pin adapter. Most all of the 90mm GM throttle bodies use the 6 Pin connector, and uses the 6 Pin adapter. If you chose to run a cable throttle body, the DBC sub harness uses standard mid 90+ IAC and TPS connections.