Welcome to the FFO!
Most of the PCMs are the same construction. They have the same number of connectors and pins
Like cars they come in different generations or pin count.
The EEC IV used a 40 pin PCM
The PCM now used us double or triple that
However the programing inside is very different for many different applications, Variables are:
Engine size
Number of cylinders
Transmission type
AC or non AC
Standard operation or special like Police or taxi
Individual calibration
Switching a PCM from one model to the other will not work.
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