I came across an old (1960s or before) reference table for Federal Mogul bearings.
It shows correspondance between Federal Mogul part #1560SA and Cadillac part #3630224 for 1949-1954 331 rod bearings.
As you can see, they were available in several sizes. I guess 10-20-30-60 mean .010 to .060" oversize bearings.
What is the use of "1" and "2", which would be .001 and .002 oversize ?
Do/did machinists commonly regrind crankshaft journals to these tiny values ?
Or were crankshafts sorted at factory, depending on quality controls ? This was/is a common practice of other car makers for parts like pistons, but it sounds strange that Cadillac did that at that time.
I haven't found a mention of oversize bearing sizes, neither in my '52 shop manual nor in my parts list.
Because of machining tolerances back then some cranks may have been undersized by 001 or 002, 010 and more under were for reconditioning purposes as a rule. No .001 or .002 cranks get refinished to that size, 10 under would be the minimum clean up, usually more like 20 or 30.