Since the writing is long gone off of the tags, I need a little help. Everything I've read, has mentioned a red and a purple wire going to the starter solenoid. Well, I have yellow and purple wires. I am assuming the purple will go on the "s" post and the yellow will go on the "r" post? Any help is appreciated.
For a 68 that is correct, Yellow to "R" and Purple to "S" some might use a red wire I dont recall but I think that is pretty standard for all. You would eliminate the yellow wire if you have an HEI setup.
350 engine converted to HEI. So, since I converted to HEI, the yellow is simply not connected to anything? Can I power my HEI via the "R" post or is it better to go to fuse box?
No, power only runs up the yellow to the coil when the starter is engaged, Better to power the HEI with a 12 volt switched wire from the firewall junction block. Are you using the original coil wire to power your HEI? The original wire is a resistor wire and will not give the necessary 12 volts to the HEI. You could replace the original wire with a non resistor wire or you could install a relay controlled by the resistor wire and have the power in wire run from the alternator/battery wire.
I had not powered HEI yet, trying to determine best source of power. Sounds like best/simplest alternative is to run 12 gauge wire to firewall fuse block? What port in fuse block would best suit the HEI. Currently, I have nothing extra run in there.
I typically just use a 30 amp relay with a wire run straight to the battery and use the factory coil wire to switch the relay. Guaranteed +12 to the HEI and you are not cutting into the original harness.