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11/13/22:After collecting all the components over the last few months, I finally installed the HEI distributor I bought from a fellow Stovebolter. It didn’t go quite as planned, learned a whole lot along the way and got to speak to a legend in this industry, Tom Langdon.

I’ve wanted to upgrade to HEI ignition since I first bought our truck three years ago. Didn’t take long to figure out the only system to install was a genuine GM distributor and it’s associated components. Tom Langdon’s converted 80-82 S-10 HEI distributor seems to be the top of the line, so that is what I set my sights on. I wanted the system with the round coil so it would look nearly stock.

Since I had so many other issues that needed attention, this upgrade was put on the back burner. About six months ago, a Tom Langdon HEI Distributor came up on “Truck Parts for Sale” forum. After striking a deal the distributor, round coil and spark plug wires were now in my possession.

The first issue I discovered was the round Ford coil did not have studs and nuts to install the ring terminals that were installed on the distributor. After researching the issue, I found that Fords that use this coil also used a special terminal clip. I decided to call Tom Langdon Stovebolt company to demystify the issue. To my surprise, Tom answered the phone. I spoke to him over twenty minutes from the issues I was having to future upgrades.

After talking with Tom, he recommend that I ditch the round coil in favor of the square one that GM used with that system, stating he had allot of those coils returned, so he no longer sells or recommends that coil. He sold me the coil, spark plugs, distributor hold down and an installation kit that included the terminal for the coil.

After receiving Tom’s goody box, I was anxious to get started with the installation. That’s when I found the second issue. The coil wire for the round coil does not fit the square coil. The square coil uses GM style ends on their coil and distributor. A quick call to Tom, and he said He did not have any to sell but I could buy one at any Auto Parts Store. Armed with that info, I went to my local Parts Store and found that they did not carry them. I then went to my not so local parts stores (three more 45 minutes away), and discovered that they did not carry them either. One parts guy said that outboard motors use that same type of coil wire and that was the clue I needed.

I found one that fit on eBay and the only issue was it was blue. Not what I was looking for, but I think I can live with that.

After much discussion previous about supplying the power for this system, with Tom Langdon and on this forum, I decided to use a 60 amp bosch style relay with the required 10 gauge wire. This simplified the installation because I already had the wire from the ignition switch on the firewall attached to the ballast resister. The starter is directly below so getting ample power was easy.

I mounted the square coil on the frame as Tom Had recommended. The only concern I had was water splashing between the frame and the inner fender, as there is about a 1/2” gap. Tom assured me water was not an issue with this coil. I used my 3-D printer to print a 1x1x4” long angle iron (plastic), to install under the coil, pushed against the inner fender to form a barrier. Probably overkill but it makes me feel better.

I spent an afternoon assembling the wiring harness prior to installation. Installation went relatively easy. I first set the timing slightly before TDC, confirmed the rotor was pointing to number one spark plug wire position, then removed the distributor. Installing the new distributor was basically the same as the original, a task I have performed many times before. I changed the plugs, fabricated and installed new Cu-Ni timing advance line, installed the new Bosch relay, the new square coil on the frame then installed the wiring harness I previously made. A quick check with a multimeter to see if I had power at the positive side of the coil with the ignition turned on, and I was ready to fire her up. She started immediately. I threw a timing light on her but found it near impossible to see 10-18 degrees advanced. I settled for tuning it by ear until I buy an adjustable timing light. I might consider adding a timing mark on the front pulley.

I finished the job by neatening up the wiring with wire ties. I’m looking forward to a test drive in the next few days, weather permiting! I am in the mountains in upstate New York!