You may have been following my search for the source of the incessant road noise. More on that in a bit.

My Question
Can you seat the bearing races too far in when reinstalling the half-shafts?
Using a piece of wood as a drift, I slowly and evenly hammered the races back into place. The rear wheels feel very tight now - much tighter than before. This concerns me. I'd think they would work themselves loose if they were too tight, but I dunno. This is my first time putting an axle back together...

I could pull the rear drums and use my axle puller to loosen the races slightly if this is a serious problem. I don't want to do that if it is not necessary

Background
I serviced and re-packed my bearings this morning. Not having new rear bearings on hand, I had planned to swap both short-shafts & bearing sets with a pair taken from one of my donor axles.

When I pulled the my car's half-shafts I found only a thinned black slime in place of the bearing grease. After removing and thoroughly cleaning the bearings, I found no sign of nasty wear on the races or rollers. I had planned to install the 65 halfshafts, but I could see some wear on the races and some pitting on those rollers, so I shelved that idea.

I considered that the heavy rumbling/scraping I had been hearing was attributable to the lack of grease and since these bearing looked as good as new, I went ahead and re-packed them. I also applied a thin coat of grease to the races and inner seals, and put the whole thing back together.

The result? No change. Still got the horrid noise.
I've positively ruled out the driveshaft bearing and the #1 U-joint. I've tentatively ruled out u-joints #2 and #2, as well as the rear bearings and front bearings. I only say tentative because I've swapped them with other used parts.

I'm fast running out of ideas for the source of this noise. I know that the noise is present when the car is in motion. Engine revs and gear shifts make no difference. Brakes only make a difference in that the car stops moving so there's less noise. It gets very bad when the car is under load (e.g. trunk full of bricks) but does not appear to be the bearings as I've swapped and/or cleaned and repacked all four wheels now.

I'm down to:
M41 gearbox (doesn't sound like it)

4.10 differential (possible, but it was cleaned, painted, a new seal was installed and it was refilled with JT7 before I put it on the car).

The wheels themselves (these are newer "winston" metric tires from Mario_E's old 1965.

This is driving me bonkers!!!