Just got this article on e-mail. Might be old, might be new, might be interesting to some:

https://www.hemmings.com/blog/2019/0...ign=2019-09-30

 

Is it time for this article again? Seems like a magazine needs to publish this about every two years or so. The reality is that after the 1965 model year, the digits meant nothing. In 1966 you could get a 4-6-2. In 1970 it was a 4.5-4-2. By 1972 you could (disappointingly) get a 3.5-2-1. And by the mid-70s, there was a 2.3-2-1.