Ed - According to the Bearing Chart in a 1954 Chevy Master Parts Book, your original Hyatt A11445 was listed as GM# 187434 and also Hyatt 11445Z. I came across a couple of NOS Hyatt 11445Z bearings offered on line from $95-$125 each, which seems excessive to me. Only one source listed a quantity of 2, and those were the $125 each priced ones -ouch!
The Filling Station offers a replacement differential carrier bearing as
FS-343 for $79.95 each + shipping. Their description indicates theirs replaces both GM# 187434 and Hyatt KA-11445-Z (which is a later designation for Hyatt 11445Z).
I think you will find these will fill your need.
