Re: Driving comparisons between the Packard Six and 120.

Posted by Ross On 2012/7/7 9:24:44

Here is a little followup: Most of the postwar inliners had their peak torque at 2000 rpm. The 54s has it a 2200 because of the cam timing change.

So, if I want to spend a lot of time at 60, and my tires are 28" in diameter, I am looking for a 2.78 overall final drive. With overdrive, that means the axle would ideally be a 3.85, or lets say 3.9, which is readily available. Packard usually provided a 4.1 with overdrive which puts the optimum speed clustered around 57 or so. (Remember this is all very fuzzy stuff with many variables entering).

And the moral of the story is that the Packard engineers were pretty clever in their choice of ratios given the types of driving that predominated then. In cars without overdrive they necessarily chose with an eye to flexibility and hill climbing. The vast majority of cars seldom saw sustained high speeds--certainly not around here as there was no place to do it.