If the rim-section (rim width) of your 1946 car wheels is 4.0", you will have limited selection in radial tires (and/or you will have to find an accommodating tire installer).

A 215/70/16 tire would need a rim width of 5.5-7.0"

I am using 215/85R16 tires on my truck (this is "high profile" tire that has a profile similar to the original bias-ply tire). They should be mounted on 5.5 min rim section wheels but my 1954 16" truck wheels have 5" rim section.