No, what I did was remove all the under hood wiring and make up my own custom harness. I bought a bunch of good quality wire, terminals, relays, breakers, fusible links, solder, heat shrink, etc. and wired things the way I thought it should be. I have added relays for the starter circuit, ignition, horn, headlights, and fans. I put in junction blocks to feed the circuits and reduce voltage drop and eliminated the regulator and horn relay. I crimped then soldered then heat shrink-wrapped every junction and protected every circuit with a breaker and/or fusible link. If one didn't know what a Firebird was supposed to look like under the hood it would/might look normal, but anyone on this site would recognize it as custom.
Seems to work.