I've lost track of the question but someone asked what the 4th gear ratio is and I repeated what I saw in Nitske's book

For the sake of discussion, I believe 1:1 describes the ratio between the transmission input and output shafts. It does not consider the effects of slip through the torque converter on engine rpm.

It is a reference to the mechanical design of the transmission, just as static compression ratio is a reference to the mechanical design of the engine. I don't know how an acceptable compression test result range of 350-400 psi (or whatever it is) confirms or rejects that static compression ratio is 22:1 (or whatever it is).

Sixto
87 300D