Introduction and electrical questions on 67 c20

[burningsquirrels]

Hey guys, first post. Long time member as occasional troll since 2006. I am helping a buddy of mine work on his C20. It has a 327 with a 4 speed. Everything on the truck was original and in good running shape, except for one of the heads that had a couple bad valve seats. Non factory stuff included just an edelbrock carb and a newer exhaust system off the manifolds. It also had a newer alternator that had two blade prongs, a battery wire post, and a ground post (more on this in a bit)

We replaced the cylinder heads with a pair of camel hump heads I had sitting around for a while, and he gave it a ten foot paint job and a new tailgate. When we buttoned it up, I buttoned the starter up and put in a spin-on oil filter adapter and replaced the cooling system. He wired up the points distributor, coil, alternator, fuel system.

Well, long story short, we were cranking but had no spark. We were troubleshooting this when we realized that both of us realized another problem that the alternator wasn't hooked up. I asked him where the harness was for it, he dug around in the fender and whoops, it shorted on the fender. Disconnected the battery, replaced the wires (a foot worth), checked fuses (looked normal), it seemed alright. We weren't sure which went to what on the distributor at the time, so we lay the wires on the side and kept crankin'.

Eventually we found that the coil was bad, so we dropped in a coil in cap HEI and it fired up on the first try like we never had it apart. Runs and drives great with the new heads and distributor. Problem that remains now is the charging system.

We're not sure about the two plugs in the middle that go to the alternator, they are arranged like this: "--" in line, as opposed to side by side like this "||". I believe this is internally regulated. I didn't see the voltage regulator, I believe after looking around here it's behind the passenger side headlight on the core support? (Truck is not here with me today, will be tomorrow).

We did some tests to try and figure out what the plugs are supposed to do. This worked fine and charged the battery before, but we don't want to just jam the plugs on and hope it works. One plug has a purple wire (which I believe goes to the ignition switch and terminal 1) and the other has a white wire (which I believe goes to terminal 2).

Is there some way we can verify which goes to which before plugging them in? With the engine on, the only place we get voltage is the normal 12.6 volts off the big red hot post, instead of the usual 13-14+ volts I was expecting. Are the terminals (1 or 2) on the alternator supposed to put out some current to tell the alternator what to do? Is either purple or white wires supposed to put out current? Is purple on 1 and white on 2 correct? Is not having these two plugged up keeping the dash from powering up? I'm afraid that we may have shorted them when the four wires got jacked. Lastly, could there be a voltage regulator still hooked up that I didn't find? The fuses check out OK. The instrument panel does not light up.

Was hoping to try and sort this out by asking the few questions above? I head back tomorrow to take a second look in the afternoon and would appreciate a hand at getting a list of things to check.... Thanks!