According to the Federal-Mogul Shop Specifications Manual:

Standard shaft size: 2.312"
Connecting rod bore size: 2.437"

A little math tells me that a standard bearing will have a shell thickness of .0625"
.010" undersize: 0.0675"
.020" undersize: 0.0725"
.030" undersize: 0.0775"

These dimensions will vary slightly according to how much oil clearance is built into the bearing shells. If they don't have an undersize marked, they're probably standard size. To get an accurate measurement of the actual thickness you'll need a ball-anvil micrometer, AKA "tubing micrometer". You can get a pretty accurate SWAG with the tapered tip jaws of of a dial caliper.

Edit: These dimensions are for the 54-62 full pressure engine. Babbit-rod conversion bearings will have a different outside diameter and width.
Jerry


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