Sounds to me like you had been adjusting them correctly, 33ft lb and back off as the service manual describes.
This page and the next:
http://chevy.oldcarmanualproject.com/shop/1948_51truck/51ctsm0307.htm

In my opinion this procedure results in a little more tension on the bearings than Timken tapered roller bearings usually get.

I too suspect that something was or is not seated fully, be it a race in the hub or the dust shield keeping the inner bearing from sitting back on the shoulder of the spindle.
Or, bent spindle might be an issue but sounds unlikely in your case.

Could be damage to a race from driving it in with a steel punch instead of a nicely fitting circular tool as you'd use in the press?

Were the hubs thoroughly cleaned of old grease and who knows what inside?

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-