According to my 1950-1965 GM Interchange manual, the axle shaft for Pontiac fits only 57-58.The differential case interchanges 1957-58 Pontiac and Olds. Ring and gear interchange Pontiac and Olds 1957-63 w/ 3.08, 3.23, 2.87, 2.69 and Pontiac 61-63/ Olds 62-63 2.56.
FWIW the interchange also states differential case interchange for Pontiac/Olds as:
53-56
57-58
59-63
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