Man I would be hard pressed not to rip and rebuild. Those are some heavy gauge wires dangling and screaming FIRE. I would order the two under hood harnesses from a company like M&H and choose to have them set it up for HEI. Most modern ignitions today can not use ballast resister wiring and need full 12 volts to the coil. You need to determine if your alternator has been modified to ONE WIRE or if it still has two connectors present. If still stock you can order a new Solid state voltage regulator that looks just like the original. If not you need to let the wiring company know you have a One Wire alternator and they can build to match. If you think you need help get someone to advise you. The two harnesses would be about $250 plus distributor, voltage regulator and horn relay if needed. The end result will be an updated and clean solution but more importantly safe.
Bill, electrical is definitely my weak point. In fact, I can never fully wrap my brain around, nor fully understand the operation, and the need for relays, regardless of how many times people explain it to me.
So I haven't any doubt that you're more knowledgeable about electrical wiring than I am. But just to be clear, I just want to point out to others that there are plenty of three wire alternators available which are both an upgrade and modern, and yet still have internal voltage regulators. I say that because it kind of sounded like you were implying that the only two choices in alternators were one-wire deals, or three wire which still use external voltage regulators like the old original 60's alternators do. But ofcourse that isn't the case.
I plan on using much of "MAD Electric" wiring products and advice. And the owner of that company, (who claims to be a former GM electrical engineer) strongly recommends that we avoid one wire alternators. He says that GM used to have one-wire alternators, and their three wire ones were an upgrade, and that now we have aftermarket companies going "backwards" by offering one wire alternators as if that's an upgrade, while the reality is that a one wire alternator is a downgrade and is more old hat than the three wire set up is. He recommends we use the 94 amp alternator that can be bought from any auto parts store for a 1984 "H.O" motor Z28 Camaro, because it's a 12 SI piece which flows plenty of air to keep itself cool, is a three-wire deal, and with a 94 amp output supplies more amperage than any of us will ever need, unless we're using an extreme sound system with huge amplifiers to shake the neighborhood with sound everywhere we drive.
BTW, with his underhood set up, he also eliminates the factory electrical buss bar, (located somewhere near the radiator I believe) which he says is the primary reason that our cars have dim headlights.