Higher Gear Ratio For '37 LaSalle-Will a '46 Cad Third Member Work

[carlhungness]

 I think the '46 Cadillac has a higher gear ratio than my '37 LaSalle which I believe to be about 3.90. I think it is possible to install the third member from the '46 into the '37 and I think the axles have to be shortened.
   Looking for knowledge of the subject. Am trying to obtain a higher gear for my '37 without changing the whole rear end. I can have axles shortened.

[Jay Friedman]

According to my 1935-55 parts manual, a '37 LaSalle has a differential ratio of 3.77.  A'46 Cadillac with a manual transmission also has a differential ratio of 3.77.  However, most '46s are equipped with Hydramatic and have a differential ratio of 3.36.