The only examples I have to go by are the 15 inch wheels used on '55/'56 T-Birds.
They are 15 x 5 with a 3.5 inch backspace. A good number of those T-bird parts were borrowed from full-sized cars and they may be the same. ???
A possible exception... station wagons in those years may have used 5.5 inch wide wheels due to heavier anticipated loads.
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