I finally found a GM bracket. heatsink & module like the one posted in this thread..
http://www.slantsix.org/forum/viewtopic ... ht=#125663
Does anyone have a wiring diagram for this setup. This module only has one connection for the pickup coil, and I'm not sure its going to work unless one side of the pickup coil can be grounded. The module in this setup is controled by the computer.
TIA ken

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Retired old Goat rebuilding a old Goat.
(85 Ram 150 /6)

How many pins does this HEI module have? Four, five, seven, eight?

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

It has 4 pins. After a 3 day search I found plugs to fit the module and the coil. The boneyards don't want to sell them for some reason. The 2 plugs cost more than the HEI unit. I've been doing some research in my FSM for my 85/ truck, and I think one of the pickup leads was grounded in the truck ECU. Friday I'll do a smoke test..
ken

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Retired old Goat rebuilding a old Goat.
(85 Ram 150 /6)

This is a picture of a Chevrolet LT1 coil, bracket and heat sink with an early HEI 4-pin module. Two wires to the distributor, power to the pink wire and a coil wire is all this needs to function. The spark looks better in person, but this was the picture we got with me spinning the distributor by hand. Cost me $12 at the wrecking yard plus some time scrubbing the stuff clean and extending the wires from the coil to the module.

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Joshua

I did the smoke test this evening and it was a great success. No smoke, but hot blue sparks at least 1/2 inch long in open air. It looks like .60 plug gaps would be reasonable...but that requires another test. My unit is slightly different than the one it the photo above. The one I have is off of a 96 chevy truck and the module and the coil have weather proof sockets. I'll try to post more details later if anyone is interested.
ken

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Retired old Goat rebuilding a old Goat.
(85 Ram 150 /6)

Use 0.045" plug gaps. Larger than that will cause a lot more problems than it could ever solve.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I would be careful with widening the gap. The arc over voltage is much higher under compression than in the open air. Increasing the gap will raise the arc over voltage even further, stressing the high voltage components and shortening their service life. Remember that a charged coil has a tremendous amount of stored energy, and once the primary circuit is opened, the coil's magnetic field will collapse and try to drive the voltage to infinity until a discharge path is created with the arc across the plug electrode. The current will ALWAYS seek the path of least resistance. If the path of least resistance is through the plug wires, the cap, rotor, or even internal across the windings of the coil itself, the collapsing field will force the current to ground.
I once had an '81 Gran Prix (I think Gran Prix roughly translates to "falls apart rapidly") that the FSM called for a 0.080 plug gap. That thing would eat up a distributor cap every 8 to 12 months by arcing over in the cap creating a carbon track ruining the cap. Forget about using cheap after-market caps. Some of the cheap ones would fail on the initial start-up. Cheap plug wires would also break down in only a few months. After a while I finally asked some of the GM techs at one of the dealers and they said to ignore the FSM and gap them to 0.060. This drastically improved the life of the ignition components. Later versions of the 3.8l used the 0.060 gap as standard.
On most modern vehicles the manufacturers seem to have settled on a gap somewhere between 0.040 to 0.050. This seems to be a good compromise between long life of the ignition components and a long hot arc.
As for the available plugs for the slant, I'm not sure if there are any designs out there that will work well with any gap set much over 0.045. Maybe some of the resident plug experts can chime in on plug recommendations that work well with modern ignition systems.

Scott (cavisco)

The Delphi-Packard WeatherPack as well as the Packard 56 connectors commonly used on older cars like slants are available from http://www.waytekwire.com/. I think you will find their prices rather reasonable compared to some restoration vendors. No affiliation; just a happy customer.