Thank you for the link... good information here but not quite the level I seek.

There are three or four ICs I have no details on. I need to get hold of some samples, remove them from the board and make up test boards to figure out the operation. Can anyone help me figure out what more common boards have the chips? I think that some of the parts may be common to any engine that has opti-spark. LT1 yes but are there others I might find in the wreckers? Did Northstar engines have opti-spark? What about some of the four and six cyl pcms around the time OBDII came out?

I could probably find dozens of Chev Cavalier ecms before finding F/Y body ecm. Best for me is if I can get my hands on a board that contains both 27474 and 144436. At least then I could get the ignition structure figured out. TPU and mosfet driver for the injectors would also be a score.

I will try to find pictures that document some of these ecms here on this site (but it's hard to search here)

Suggestions?