Are you guys using a painless kit? Or is there someone else making a harness, or are you building your own?
I built my own harness, but I've built so many I know how. A kit is a good start, but prepare to splice a lot of wires since they will be short.
For me if it's a carb you can use a basic kit from American Autowire, Painless, TCI ect.. all work fine. As stated before making your own is not that hard with a basic understanding of 12 volt electrical systems. Now if your going fuel injection you can adapt an existing engine control harness and PCM/ECM controller. Some of the systems will need a re-flash to remove security systems, some will not, depending on age. You can also buy aftermarket fuel injection harnesses. I have used Painless and The Detail Zone with good success. The whole fuel injection issue is more work up front, but well worth it in the long run IMO. Good luck, Fasttoys