I am only here to help ... I don't like, nor seek conflict. Your posts are informative, and no doubt based on a lifetime with GM products. That said, GM does not provide its Techs with training in how to build Hot Rods, nor how to run the systems in a non-OEM configuration.

You are trying to help Dave, but are making an educated guess a lot of the time - no problem, just indicate when these are guesses or logical inferences.

To getting things back on track to assisting Dave ...

The diode discussion stopped short of where it should have gone. The diode part number discussion took things in a non-productive direction. The answer as you guessed, was that these are integrated in the under-hood electrical centre - so therefore, there is no part number for these. Where the discussion should have gone, was to why these are used, when these are used, and is there a pattern per use versus controller. Yes - there is.

On CAN Bus comms issue - the wiring harness in a Hot Rod does not need a second 120 ohm resistor, if only an ECM and TCM are on the bus. Lots of threads on the internet regarding this topic - with arguments on both sides - the smart people have tried it both ways, and realized it doesn't really matter - the comms function either way.

Hopefully that is enough of an olive branch to get things back on track ...