Think you have your generations mixed up, 76 was smack dab in the middle of 8 track hayday, so i'm pretty sure it was at least an option. By 86 though, not so much. 86 trucks definitely had casette tapes as an option, my 85 and 87 both did. In fact i'm not sure if CD player was an option yet.

Actually I looked on wikipedia, and found this:

The first car with an OEM CD player was the 1987 Lincoln Town Car, and the last new car in the American market to be factory-equipped with a cassette deck in the dashboard was a 2010 Lexus.

2010 seems really late for casette tapes, but hey...

 

I was wondering if someone would bother fact checking the dates. Irrelevant to the point though. Technology marches on. In the place of a single cassette tape you can fit a TB of movies and video.

 

My wife recently bought a new car (a Kia) and a CD Player isnt even an option.

But it does bluetooth and has aux ports and all that jazz.