- The FuelTech FT600 PRO V8 complete harness is the best link between your FT600 ECU and V8 engine. It comes pre-terminated to suit a V8 engine with all relays and fuses for a simple 3 wire battery hook up and ignition power. It has a 37-pin firewall connector to make installation an easy task and with the modular construction, adding a second set of injectors or individual coils is as easy as connecting add-on harnesses utilizing the built in output connectors. Each connector has its own label, and the connectors and harness insulation are heat, moisture and oil resistant.