On my '60 Suburban, I've yanked out the old 350 that had points, I dropped in a different rebuilt, 1974 block, which will have HEI. I'm basically going back through and trying to clean up all the cut wires, crusty harness(s), etc and running new wires. The problem is there are wires I don't need, wires that were cut/spliced/etc, so the diagrams are somewhat helpful, but not totally.
To the starter 'S' terminal I believe that's the purple wire, which is still there I believe. It goes back to the ignition switch when the key is in the 'start' position, correct?
Yes through the forward firewall connector, and the neutral start switch, if you have one, then to the key switch.Standard shifts have a switch on the transmission.
I don't believe I use the 'R' terminal, but one diagram I have shows a feed from that going to an internal coil (
Points, the coil is external) distributor(which isn't that the same as the HEI?). Do I do this or not? First time I've seen it.
This is the R wiring going to the external coil (OEM) It relays a full 12 volts to the coil during starting only. Then in normal running a wire from the firewall block to the ballast resistor then to the coil Positive terminal supplies ignition voltage.
For the HEI, the RED wire will go back to 12+ always on power from the ignition switch, correct?
Somewhat, there are several ways to do it but it must be key on only power. Some have spliced into the pink wire on the ignition switch, some like the cleaner look of pulling The ignition wire out of the firewall block and installing a new pink ignition wire, omitting the ballast resistor, to the HEI distributor.
Here's a diagram.
The green to the tach, which I don't have yet, but will add later, so it'll get wired into the plug at the firewall.
Follow the tach wiring instructions.
As for the alternator, I currently have the two wire style, but will probably upgrade once I start adding things back in like a radio, etc... On that I'll have more questions , but from the diagram I'm looking at it appears I'll run a heavy gauge (fuseable link?) wire from the battery terminal side of the starter(or + terminal post if I add one?) to the back of the alternator. I'll also run the red wire from the 2 plug terminal on alt to the battery terminal spot on alt and then what is labeled as brown from this will go back to the dash, to what I'm presuming is the gauge in the dash. I have both a guage and the idiot light, should I/can I use both? Anything special to wire in or do I just run the wire there....something mentioned a resistor if not using idiot light.
Read this for now and post back when you're ready.
http://67-72chevytrucks.com/vboard/s...d.php?t=417872
What I am somewhat confused on is the horn relay and where that comes into play. Again, I have the diagrams, but not sure they were followed last time when it was converted to a 350.
The horn relay was used as a junction block for the simple earlier systems through the 66 years. The battery alternator and regulators all joined there and the power for the rest of the truck came from there to the cab. You are talking of re routing the power wires to the starter with fusible links and using the starter post as the junction.You might disable the battery gauge if you do this, since all the battery and alternator power runs through the ammeter on these earlier trucks prior to 1963.
As for wire sizes, I think I can easily find that, but if you have recommendations that is great. I think 12gauge is what the factory used on the HEI's in '74 and a 10amp fuse.
Fuse is optional. I doubt I need that much for the tach side, should 14 suffice?
You should get a harness for the tach. For the 'S' wire on starter, the oil, temp, etc, it appears the diagrams show 20g wire, because I don't want to buy a bunch of different gauge/colors of wires, I'll likely run 14 or 16, unless any of those need heavier.
The S wire needs to be 12 gauge from the key to the solenoid.
The output for the alternator should be 10 gauge.
I'll probably be back for advice in a few other areas, as I want to add a neutral safety, back up lights, etc...