I do have a bad memory when it comes to certain things that you bring up. ;-)

My recollection is that GM had decided that it didn't make sense to do the engineering necessary to improve the mileage and emissions on all of their engines. So, they thought that if they put Chevy engines in Oldsmobiles they could save some scratch and nobody would care. Until old geezers would buy a Delta 88 and then go to change the oil and find out it had a Mouse motor in it. And they sued. Then GM started putting their disclaimer, "May contain an engine from other GM divisions...".

Let's see...

While the Wikipedia "Oldsmobile" article mentions the production issues, this story from the NY Times (just the first sentence or two is free) is closer to my recollection: http://select.nytime...994DB405B878BF1D3

G.M. Calls Its Engine Swapping Innocent, But to the Brand-Faithful Buyer It's a Sin

By REGINALD STUART Special to The New York Times

March 15, 1977, Tuesday

Section: Business & Finance, Page 51, 1240 words

DETROIT, March 14--Small wonder that the General Motors Corporation is putting Chevrolet engines in Oldsmobiles. It installed Oldsmobile engines in Cadillac's new luxury mid-sized Seville.


IOW, it was GM being GM... ;-)

Cheers,
Scott.