Gen 4 LS
https://github.com/rusefi/rusefi/wiki/GM-E38
https://github.com/rusefi/rusefi/wiki/GM-E67
73+80 e38 ECM, used 07-14 trucks/suv
https://www.maxxecu.com/webhelp/wirings-pluginecu-chevrolet_corvette_c6_e38_ecm.html
https://lt1swap.com/E38%20ECM%20Connector%20Pinouts.htm
x+y+z E67 ECM used 2007+ envoy, trailblazer, saab 97x, rainier, impala ss, and others
https://www.lt1swap.com/pcm_identification.htm
E38 and E67 are very comparable in terms of processor speed, OS design, etc.
E67 was the "high IO" version, E38 simpler version
All PowerPC. There are early (2006-2009) and late (2010-2013) models of each which have incompatible / smaller-larger processors and cannot run the same OSes obviously. Early and late ECMs are plug and play with each other
If I had to make an educated guess, GM used the E67 for their GMPP (GM Performance Parts) control packs because they had more of them left over. The E38 was the more popular application by far.
https://github.com/rusefi/rusefi/wiki/GM-E67
See also Gen-5-LS
