HEI in Mopar ECU casing

Radio shack carries thermal compound, and it's where we get ours for our HEI kits.
The UCU's can easily handle 200+ degrees, but they MUST have a way of disipating the heat buildup from the electronics inside them.
This is where the thermal compound comes in because it transferes that heat to the device it is mounted to.
They can even be mounted directly to body metal as long as the thermal compound is between it and the metal and there is a fair amount of surface contact.

There are two things that make putting them in a Mopar box a bit of a challenge and those are keeping the box stock looking (the point, right?)
And getting the ECU mounted inside there with a good reliable ground.
I found that using wire and a bolt/nut work best for the grounding of the ECU because you either need to put extra screws through the box (not stock looking) or use the same screws that mount the transistor and heatsink.
The screws that mount the transistor and heatsink are too short and large around to be useuable for this, and longer/different screws don't look stock.

You can however use the stock screws and put an eyelet for a wired ground to the case, and machine screws to connect it to the bolt holes on the HEI ecu.
It will still need to be in contact with the Mopar box case or separate heatsink with heatsink compound.

Also once you take all the old crap out of the original box the transistor mounting screws are now too long unless you use spacers inside the box, and when you doo that it takes up the room needed for a heatsink capable surface.

I finally conceded and just let the screws look longer than factory. (lesser of the evils):D

Dealing with the pins for the harness connector is fun too, but epoxy works well for this as I wasn't going to leave part of the original electronics board in there to hold them in place.
Without part of the original board in there, they need to be stabilized a different way.