Tapping into the collective braintrust

Thanks for the replies fellas, but I'm obviously not describing it good enough. Sorry about that.
What I'm trying to describe is not a "ribbon" style speedo, where a colored indicator travels across a speedometer. (Olds and Desoto examples)
The one I'm trying to describe has the numbers on the rotating drum. There is a small opening, or window in the dash where just the speed you are travelling shows. It's sort of like the picture below but this is not it. The photo is from a 67 Oldsmobile, and he did not have one of those.