The LeMans Gets Hypersparked

New Distributor, Ignition Box and Coil for the LeMans

Having started down the road of modernity with the installation of Holley’s Sniper EFI throttle body in my 1972 Pontiac LeMans, I decided to go all in and add their Hyperspark distributor, coil and ignition box. As chronicled here, the Sniper EFI throttle body was operating to expectations. Cold starts and idle were a breeze, throttle response was good and all-around drivability impressed. However, Holley had these products out there that would allow the ECU to control timing, bringing the system to the next level. I sought more control, better gas mileage, maybe even better performance. In this post, I will go over what I bought to make this happen, how it went together and the results of this effort.

I purchased the Holley Hyperspark EFI distributor for Pontiac (#5565-314BK), ignition box (#556-151) and coil (#556-152) from EFI System Pro. This supplier has great technical information on their website and offers free tech support to those who purchase products from them. They also offer unique products such as the progressive linkage kit for the Sniper throttle body. As of October 2021, the cost for the three items I purchased was $531.76. Prices for everything are on the rise, so don’t wait if you are interested. The parts shipped right away and I received them one week later (shipping from Florida to Washington is as distant as two points can be in the continental U.S.)

My first task after receiving the package from EFI System Pro was to locate a place to mount the coil and ignition box. The outgoing distributor was a GM style HEI unit with an integral coil and ignition. There was a free spot on the passenger-side firewall, and there were even four bolt ends sticking through the firewall to which the a/c system was mounted. I took a piece of 1/4″ thick woodfiber laminate (cutting board material), painted it black, drilled and tapped holes, and then bolted the coil and ignition box to it.

Mounting plate on the firewall.
Coil and ignition box on mounting plate.

With the addition of the new ignition box, and some other items I was adding, I decided I needed more 12-volt power sources. Painless Performance makes a weatherproof auxiliary fuse block that provides power to three accessories with the ignition on. Their part number for this item is 70213. It is called the Cirkit Boss Auxiliary Fuse Block. Yes, I know they spelled “circuit” incorrectly. I mounted it to the same plate as the coil and ignition box, ran a wire to the fuse box, one each to the battery positive and negative.

Painless Performance Cirkit Boss #70213
Holley’s clear plastic distributor indexing tool makes installation a breeze.

Holley makes installation of the distributor so simple that a kindergartner with a complete lack of mechanical acuity could do it. The most difficult step is finding top-dead-center on the compression stroke. That’s how easy installation is. Once the engine has been rotated to that spot, remove the old distributor, stab in the new one, set the clear plastic cap that Holley supplies on top of the new distributor and rotate the distributor so that the rotor falls in place on the clear cap. Tighten the distributor hold-down nut and move on to the next step. Kindergartners throughout the land should demand their parents let them install this distributor in their muscle car.

With the distributor in place, I proceeded to connect all the wires. Most of these wires just click in to place, connecting the distributor to the EFI unit, ignition box and coil. The system needs power from the battery and a keyed 12 volt ignition source, and it is grounded to the battery. I removed some of the wires from the system that weren’t being used. Holley makes a tool to do this and plugs that go in place of the wire to provide weather protection. Routing wires with some semblance of neatness was my biggest challenge for this project. Through much trial and error and the depletion of most of the world’s zip-ties, I achieved a neatness level that I felt was sufficient. The final step in the wiring process was to connect the spark plug and coil wires.

Clean-up of the wiring has commenced

With the wiring complete, I plugged in the handheld display to the EFI in order to update its programming. I had to tell the EFI that the Hyperspark distributor was not installed and that it would need to control the timing. I followed Holley’s instructions for programming the handheld unit until I reached a step where it told me it couldn’t communicate with the ECU. I know that communicating is difficult sometimes. We’re tired, grumpy, have had a few too many bottles of rye whiskey. The ECU was as done communicating with the handheld as my wife is with me when I’ve done something stupid. Several times I attempted to perform this step, but the ECU just wasn’t having it. My hope was that the handheld unit would just apologize so we could all move on, but it just wasn’t meant to be. I contacted Holley’s customer support and followed their instructions, which included verifying the battery had twelve volts and updating the firmware on the ECU (which was impossible since the ECU had gone in hibernation).

As my impatience wore on, I finally decided to purchase a new Sniper throttle body. I reasoned that I wanted to install Holley’s EFI system on my 1971 Corvette, so I could just install the new throttle body on the LeMans to get it running and then when the old one is fixed, I could install it on the Corvette. I received the new Sniper unit, installed it with the existing wiring in no time, updated the firmware, programmed its ECU, and the 400 cubic inch Pontiac V8 fired immediately. “Thank God”, I thought as I turned the key to shut the ignition off. Except the engine didn’t shut off. It just kept running. I pushed the parking brake pedal to inspect what was going on, and the engine shut off. “Well that’s a weird feature that Holley likely didn’t intend”, I thought, as I prepared for my test drive.

My first drive with the new set-up was a resounding success. Despite the ECU having to completely relearn its programming, I found the LeMans pulled noticeably harder to redline than it ever had. The car feels like it has had new higher compression heads installed. There is no sacrifice in drivability. The water temperature stayed below 90° F on this warm summer day and the air/fuel ratio was spot-on. I was quite pleased that the struggle in dealing with the failed ECU paid off with the improved performance thanks to the new distributor, ignition box and coil. The only issue with the system I have is the run-on until I engage the parking brake. I’m sure this will be a simple diagnosis of the wiring, but it will involve cutting loose the thousands of zip-ties that keep the wires organized. In the mean time, it’s never a bad idea to set one’s parking brake.

Holley’s Sniper EFI system is a great solution that I would recommend to anyone wishing to improve the drivability and tunability of their American carbureted car. There is some wiring involved, the fuel system needs to be upgraded and the fuel lines have to handle 60 psi, but the effort it well worth it. As the ECU learns the engine, it will only get better. While it is a learning process for the ECU, it is also a learning process for me. Eventually, I will learn to fine-tune the settings with a laptop to perfect the tune even more. With an electronically controlled distributor, I will be able to advance the ignition curve to make more power throughout the Pontiac 400’s modest rev range. As for installation of EFI parts, I believe that I’ve exhausted that route and can look to other performance avenues, such as heads, in order to boost performance.

Next up… look for the Corvette to benefit from an EFI install. Also, what am I going to do with these extra Quadrajets carbs?