Good to know about those tapered bearings (no longer available). Sounds like so much other imported "restoration parts" they look about right but the fit, function, and usually reliability suffer.
Whoever had those bearings made shouldn't have had much difficulty researching and specifying the very same diameters and tolerances on the new bearings as the original ball bearings had for OD and ID. Not that it matters now but I wonder if they got that right or didn't try, and/or if they just weren't made to spec?
I had forgotten the 4100 and 4400 use the same axle, spindle, and bearings as the 1 ton. So again the original bearings aren't really deficient in weight capacity for a 1 ton.
Mostly people might be confused by seeing ball bearings as wheel bearings and wonder why they didn't use taper roller bearings. This leads to a desire to find tapered bearings "just because" and not because of any significant shortcoming in the ball bearings.
Grigg