The speedo on my '68 VW went to 85. I could cruise for hours (this was in the '70s) at that speed. One time, after catching a GF out with another guy -- she said she was busy that night -- I went for a drive and got the needle well past the 85 mph mark... extrapolating, I guess it was around 100-105 mph. However, at that speed, the steering no longer worked -- infinite understeer
One of my friends had a Buick Wildcat -- 455 cu. in., 4bbl carb. Top indicated speed was 120 but he managed to get it well past that mark ~140. At that speed, you could watch the gas guage quickly move towards E.
When I was a kid, our neighbor traded in his Belair wagon (see my avatar) for a 1964 Corvair Monza. Top indicated speed was 110 or 120. He took my dad and I out for a test ride and pegged the needle.