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I've had a good number of requests from both this forum and P.M.'s asking if I did a GM coil-pac. conversion tutorial when I converted my'80. Simple answer - no. So when I was installing the rebuilt '79 carbs for set-up and syncing I thought I'd take some pictures of the wiring and installation specifics for those that have been interested. That of course led to this: !
NOTE: To facilitate the GM coil-pack being located to the bottom of the OEM coil-tray, the air-injection reed-housing must be removed from the cam cover. I "shaved" the housings over 30 years ago simply to get rid of the smog-crap. done simply with a hack-saw, file and emery cloth and blocked the air-injection holes with a high temp "metallic" epoxy.
The problem with the typical location of the Coil-pac is that the obvious place for it is in the tool-tray. The additional length of the ignition-wires was of no concern nor was lengthening the other required wires. The issue for myself was the loss of the tool-tray itself and the awkwardness of changing the air-filter. One advantage however was the ability to remove the cam-cover without having to deal with ignition-coils. Removing the cam-cover now is still reasonably easy with only 4 machine screws to remove. As easy if not easier then the stock coil set-up.
I'm not concerned about the heat affecting the coils. Although i believe the OEM coils cracked (in part) as a result of heat the GM coils were designed for this environment based on where they're mounted.
Some minor adjustment to some of the wiring harnesses routing and connectors location was required for ease of install and future service.
There are too many variations of the "how to's" to detail every nuance and procedure for doing this re & re therefore the pictures are intended to be self explanatory for those capable and I hope this enlightens !

Nice change over did you have to make a new mounting bracket for the coil pac? Or were you able to use the old coil mounts.

Thanks for the images.

Good question ! The GM coil I used already had the 6 holes in the body. I simply tapped them for an appropriate thread. The frame-plate used for the OEM coils was drilled for 4 of the corresponding holes (front 2 and middle 2) and the bolts used simply drop-down thru this plate and directly into the respective coil-body holes. There is virtually no room to use stand-offs thus the need to use an electrical insulator between the frame-plate and the coils' terminal side. The rear 2 holes of the coil are too far past the mounting plate and are not used.
For this application it's critical that the wiring to the coil terminals be laid-out as in the picture (attachment). Wires that crossover can be a potential "short" and there is virtually no room for the additional height created by 'stacked" wiring.

Thanks for the link scotch! Very nice. There is only one problem - I love my polished reed valve covers!