I have a similar problem as Jenkinen ( who has a Ford). I was told that my engine came from a 1983 or 1984 Chevette. The serial number on the block is EY139154 and the 4 Speed Trans is 1EY139154 I think.
I called the local dealer — no records — that far back.
Bill, I have a 1986 Chevette manual that shows the 86 engine # to be CT- . I did not see anything starting with EY for 1986. My engine # is CT- 38123 ,which is one digit less than yours The CT in the manual also indicated a 2 barrel carb engine whigh mine is. I looked on the site that luvmytd linked to but only found V8 info, maybe I didn’t dig deep enough,it’s an awesome site.What I saw in my book only shows that it’s not a 1986.
You may want to search this forum for Rick Drake, HE IS THE CHEVETTE EXPERT according to what I have read about him.