The 3800 coil pack -- there is a aluminum mounting plate underneath that the pack bolts to. Should there be some kind of conductive grease to aid in heat transfer?

I have mine mounted where the Fiero battery was traditionally located so it is in a cool place. Nonetheless, do these things heat up?

Yes, the aluminum bracket acts as a heatsink. If you look at the bottom of the ignition module, the shiny metal part needs the heatsink grease.

The aluminum plate is part of the ICM. Heat sink paste should be applied between the ICM and it's mounting bracket, to give heat a path to move away from the ICM.....LINK

Interesting...thanks

When I removed the 3800 coil back from the original mounting bracket there was no grease between the bottom ICM and the bracket. I just mounted the coil pack to the old battery bracket with bolts spacers and nuts and that was it. No grease and 7 years later all is still working.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

I've never seen thermal paste on a 3800 ICM....

Kind of makes me wonder, if they are physically touching why is there a need for some kind of paste? Is it so they don't fuse together?

I know on the original stock setup (the old 2.8) GM later went with some heat shielding, and even a tube with a blower to keep the ignition coil from overheating. Sitting in the heart of the engine, they were known to give up the ghost, burn out, and so I also kept a spare. And, also a ignition module. Oh, the good ole days.

[This message has been edited by RotrexFiero (edited 04-17-2018).]

The DIS ICM generates heat, just like the stock Fiero ICM. The difference is that the DIS ICM isn't installed right next to a hot exhaust manifold. And since the DIS ICM is physically larger, the heat is spread out over a larger area. That said, it still generates heat, and that heat needs to be dissipated.