You must identify the connections wires youll need and get rid of the rest. This is a basic tbi harness for all engines using ecm 1227747 and 1228746 type ecm many others can be used.

4 3 Chevy Tbi Sensor Wiring Diagram H1 Wiring Diagram
Tbi conversion wiring diagram. What is covered here is generally applicable to most tbi systems but we will be putting. Wire harness can be pulled from the factory car and reworked for a conversion. A stock harness has a ton of circuits you wont need for a conversion. It included the tbi unit the intake manifold the ecm computer the distributor the wiring harness and most of the sensors. Basic connections are standard but it is easy to customize one for your needs. Using the pinout diagrams identify the circuits you want to keep.
There will be a lot of extra things dont worry about them now grab it all as whole as you can. Generic tbi fuel injection block diagram acronyms individual components and their function schematic diagram the actual installation theory and modes of operation calibration equipment variables the subject of this session is throttle body fuel injection. It much more economical to use a factory tbi wiring harness from the wrecking yard donor vehicle or ebay. The 454 is larger with close to 2 inch bores. It is recommended a tbi from about the same size engine to be used in your conversion or larger for high performance built engines. First you need to go to junk yard and pull the engine efi harness or complete system if you can.
Typically technical support is limited to the customer with only a harness purchase due to the complexity of variables we have no control over. I downloaded several pinout charts and wiring diagrams and began studying every detail. I ended up with a complete system from a 91 305 camaro for about 140. The injectors are different sizes. Its also a lot of work. Tbi wiring harness conversion.
I jumped on ebay and starting bidding.