Quote Originally Posted by 2INSANE View Post
I have seen 1981 stamped on a few red blocks.

https://www.dieselplace.com/threads/...-block.340496/

Still having a hard time trying to find one. :-/
They were unique to the 1982 model year. Of course, they were cast in 1981. I would expect, probably most of them were cast in 1981.