1974 Brain Box saves the day.

Here is some great info on the internal TO220 and external T03 Transistors

TO220_TO3.png

So in comparison the TO220 is what Standard Products LX100 module is using in their new builds, exact copy to the one pictured above here on the left.
The Mopar Brain Boxes used the TO3 pictured here 3rd from the left, that had much better heat dissipation and larger surface areas to absorb the heat.

Pictured below the New Build LX100 that uses the smaller TO220 transistor, with the lesser heat dissipating capabilities.

lX100guts.jpg

InternalHeatSink.jpg