This is a nice bracket that mounts the GM HEI module to the bottom of any Chrysler V8 electronic distributor. Bolt this on and dump the ballast resistor forever! It is also very nice for use in older Mopar vehicles where you don't want to mount a large ignition box to your firewall. This is the cheapest route I know of to obtain a powerful ignition system for your mopar.
The Chrysler distributor wires from the pickup plug right into the GM module. The other two terminals on the module go to the coil. The bracket mounts the module beneath the vacuum advance to partially hide it and provide full rotation of the distributor for ease of timing. Hiding it under the vacuum advance also helps to maintain a clean appearance.
The bracket mounts to the bottom of an original distributor casting using the original drain holes on the distributor. No drilling is required. Just file away any casting flash and tap the drain holes to bolt it on. Note that new aftermarket castings will not have the drain holes in the same location and may require drilling the bottom of the housing in order to mount this.
This bracket can be used on both small and big block Mopar V8 electronic distributors. That is; 318, 340, 360, 383, 400, 413, 426, and 440. It will not work on the Mopar slant 6 electronic distributor. Sorry.
For older motors like the 331,354,392 Hemi and poly motors, I recommend purchasing a new oil pump shaft from Hot Heads to adapt the later small block Chrysler distributor to work with them. The photo below shows the distributor on a 4-carb 392 Hemi. No clearance problems even in a tight space like this.
The bracket is aluminum which has been coated with a gold-colored film to prevent corrosion and comes with all stainless steel hardware and electrical terminals for the pickup. Full wiring and mounting instructions are also included.
What is HEI?
HEI is a term used by GM that stands for High Energy Ignition. An HEI ignition system uses a highly efficient control module that is capable of switching a large amount of energy to the spark plugs AND a high power coil with low primary resistance that can provide that power. Power is current, voltage and time so if any of these factors are lessened, the power available to your plugs is decreased.
Are all electronic ignition systems HEI systems too?
No. The original Chrysler electronic ignition system is not an HEI system. First, it requires a ballast resistor in the primary circuit to decrease the power going through the control module. It was not designed to switch that much power and will fail if you run it without the resistor. Second, it uses a relatively low power coil. The old canister style coil can't put out the kind of power that an HEI system can without overheating the coil.
Is Pertronix an HEI system?
Ignitor I
The Pertronix Ignitor I is not HEI becuase it requires a minimum of 1.5 ohms primary resistance similar to the original Chrysler system.
Ignitor II
From the description of the Ignitor II, it sounds like it uses technology similar to the original GM module, so qualitatively, it may perform similarly. I have never used the Ignitor II to compare it directly.
What is the difference between an HEI coil and a canister style coil?
An HEI coil has very low primary resistance, typically in the range of .1 to .4 ohms. This is the total resistance of the primary circuit and allows a large amount of power to build in the system. A canister style coil typically requires from 1.0 to 1.5 ohms to survive without overheating. The coil used in HEI systems is a different design, called an E-core because of its shape. This design of coil is inherently more efficient, resulting in less noise (good for computer systems) and less heat. The picture below on the left is a typical canister style coil, and the one on the right is an E-core coil. Both pictures are from www.summitracing.com
Which settings work best with the GM HEI module?
1. Re-gap your magnetic pickup to be as close to zero clearance as possible without hitting the tangs as it rotates. You should feel the magnet pull as you slowly rotate the shaft past the tangs. An excessive gap requires higher rpm to create a proper signal, making it hard to start with a slow starter.
2. Re-gap your plugs afterward (usually required!). An excessively close gap will generate too much current and can over-load the module. Most engines with 9.5:1 or less compression perform well at around .05" of plug gap with a strong E-core coil. Weaker coils or higher compression will require less gap.
Can I use an HEI coil on my Chrysler electronic ignition?
Yes you can because both systems use coils with primary resistances of around .5 ohms. However, you must retain the ballast resistor for the control module, so the total resistance will still be around 1.5 ohms and the power that your coil will put out will be limited by it.
If I use a GM HEI ignition module, can I remove my ballast resistor?
Yes you can as long as you either
1. Use an HEI E-core coil with low resistance or
2. Use a canister coil with 1.0 to 1.5 ohms resistance. This resistance is required for the coil, not the ignition module.
You must retain the ballast resistor if you wish to
3. Use the stock Chrysler coil with .5 ohms resistance. The ballast resistor here will prevent the stock coil from overheating.
The HEI ignition module enables you to use less primary resistance, but will function fine if you wish to use more resistance.
The price is $24.50 + $5.50 shipping (anywhere in US) for the HEI conversion bracket and all stainless steel hardware to mount it to your electronic distributor. A discounted shipping rate will automatically be applied for multiple orders. Contact me for shipping rates outside the US.
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