Replacing my resistor wire with HEI power supply wire, in pictures

[dmjlambert]

Here is replacing my resistor wire with HEI power supply wire, in pictures. This is on my 1969 CST/10 pickup with a 350 CI engine and TH400 transmission, and an HEI from a later model truck to replace the original points distributor and coil. I looked online and didn't find a lot of pictures regarding this, so I thought I would contribute some. I was a little afraid of this job when I started, but once I got into it, I realized it was quite easy, and it took 15 minutes.

Part 1

First I had a look at the wiring diagram and noticed the white/orange/purple wire goes to a yellow wire, which then goes to the starter and coil. During starting, the starter feeds 12V to the coil, and when the truck is on but not starting, the resistor wire feeds less than 12V to the coil.

Now, having a look at the truck, the yellow wire where it splits and goes to both the starter and the coil is clipped, and no longer goes to the starter. It just goes to the distributor. This resistor wire leading to the yellow wire is no longer suitable, now that I have HEI, because HEI is supposed to be fed 12V. The pictures show:

Wiring diagram.
I found the wire where it comes out of the bulkhead connector.
Looking under the truck where the transmission bell housing is bolted to the engine, a clip holds the wiring harness neatly and that is the point where the yellow wire comes out of the harness. There is a crimp connector to extend the wire that used to go to the starter, to make it longer to go up towards the distributor. I will clip off the yellow wire extension of the resistor wire, and leave the resistor wire unused.

I ordered a replacement wire with connectors already attached, from YearOne.com, part number L00510, https://www.yearone.com/Product/1967...c-truck/l00510

[dmjlambert]

Part 2

Loosen the bulkhead connector with a 3/8" nutdriver, and slide it apart. Notice the white wire that is cloth-wrapped, that is the resistor wire that leads to the yellow wire. From the inside of the connector, squeeze the terminal with needle-nose pliers while pushing it gently toward the back of the connector.

[dmjlambert]

Part 3

The old terminal will come out the back of the connector, still attached to the resistor wire. I will fold this wire out of the way and leave it unused. Insert the new wire from YearOne into the back of the connector. When I push it all the way in, it holds in place nicely, although I did not feel or hear a click.

[dmjlambert]

Part 4

Re-assemble the bulkhead connector and screw it into place.
Test to make sure with the key in the on position and in the start position the wire gives 12V.
Route the wire neatly along the firewall plastic wiring gutter and plug in to the HEI distributor.
That's it.

[VetteVet]

very nice job and great pictures as well. Although this modification is well known, I have never seen it pictured as well as you did. The explanation is easy to understand also. This should be in the FAQs.

[fleetsidelarry]

x2 on all that VetteVet said

[lyrikz]

Originally Posted by dmjlambert

Part 4

Re-assemble the bulkhead connector and screw it into place.
Test to make sure with the key in the on position the wire gives 12V.
Route the wire neatly along the firewall plastic wiring gutter and plug in to the HEI distributor.
That's it.

Funny story about this change. My blazer already had an hei on it. The PO ran a wire from the fuse box, through the firewall and to the hei. I removed that and then ran the wire just like you did. The funny part was those two yellow wires that go to the starter and the coil were just left dangline, LIVE!!! I had no idea what that wire was for until i just saw this picture.

Nice writeup.

[dirtyjim]

those hei lead wires from m&h make it almost to easy and at $6 its pretty much what it cost me to make one. I try to keep a couple of them on hand

[Sturvin]

Sure, post this a month after I convert my truck...

But good write up though, I'm glad you showed re-pinning the harness, definitely the right way to do it.

Fun fact, a standard spade connector will work in place of a Packard 56 if you can't find one. And I sealed my harness up with hot glue afterwards.

[CW4B]

Great post and great pictures. Previous owner of my 70 C20 ran a wire directly from fuse box, works, but your method is what I will do when I rewire everything.
Thanks.

[gmachinz]

Originally Posted by Sturvin

Sure, post this a month after I convert my truck...

But good write up though, I'm glad you showed re-pinning the harness, definitely the right way to do it.

Fun fact, a standard spade connector will work in place of a Packard 56 if you can't find one. And I sealed my harness up with hot glue afterwards.

I would not suggest using a standard male spade terminal-56, 58 and 59 series male terminals all have a tang which locks into place of the receiving cavity-standard male spades do not. So at the risk of having the terminal slide away from the adjoining female terminal, do not use a regular spade-use the proper mating terminal.

[BILT4ME]

Excellent thread with pics and part numbers!

We have been fighting a miss in the 2000-4000 RPM range during medium (cruising) throttle. I figured swapping the resistor wire was THE solution and am disappointed that it did not cure our issue.

This is something we still needed to do, regardless.

With these pics and info, it was literally a 15 minute job.

Thank you for taking the time to post all this info to help out all the rest of us!