Electronic – finding old datasheets

I am reverse engineering a old circuit board, probably from the late seventies (specifically an Enteron sk-1600-a industrial controller), And I am having trouble finding data sheets.

Firstly I am guessing that Motorola has sold off the divisions making many of the chips on this board and that they are now sold under some other name (ie Motorola moc3021 is obviously from how it is used on the board an opto-isolated triac driver and Fairchild moc3021 fits and has the same pinout, similarly their uln2003a could now be made by texas instruments although using a darlington bridge with flyback diode seems like overkill for driving the moc3021, and the mc14020b could fit the counter by on semiconductor as it is near the clock crystal).

Secondly I am guessing that some have gone the way of the dodo like the ami 8616 (looks like an eight bit processor) and the ami 8424 (probably a parallel io chip).

If anyone can partially endorse the modern data sheets (these parts are mostly compatible with their predecessors) or even better has the right data sheets, It would certainly be appreciated.