Thanks to everyone for the answers. It's a 318 in a '73 Plymouth Satellite (my daily driver) but it isn't the original engine. It's date stamped 1984 so who knows what that engine was from...I think I mentioned that in my original post...don't remember.

Anyway, thanks to all for the information. It's no wonder I've never paid any attention to it. It doesn't seem to effect the way the car runs and I've driven through the Chicago WINTER 3 years in a row!