What are the differences between 722.3s for different applications? Obvious to me are the bell housing bolt pattern and tail housing speedo drive. What other characteristics are or can be different?

1) Torque converter stall rpm. Any other TC differences within 722.3s? Multiplier ratios?

2) Vacuum modulator. What differs besides the color of the plastic case?

3) Valve body. Gear selection and shift timing based on selector position, modulator vacuum, control pressure input from engine throttle, centrifugal governor signal, kickdown switch signal, instantaneous gear setting. Oh, inane second gear start. Anything else?

4) Centrifugal governor. Is this what tells the transmission how high the engine can rev safely; i.e., when to downshift or else?

5) Secondary pump. Doesn't affect behavior.

Aside from interfaces and possibly beefier components, what is different between, say, a 722.370 (S500) and a 722.315 (123 300D)? Why can't Brian just swap a 722.321 (87 SDL) valve body into his 722.351 (300SEL) to have first gear start?

Thanks,
Sixto
87 300D