Question about tires for a 68 dart

Most that I have seen had Goodyear Custom Power Cushion whitewalls. Don't know who the other OEM suppliers were in '68. Size would have been 6.95-14. Possibly had a belted tire. This size corresponds to either a D letter size or 175 metric. Most will say that it equates to a 195 in metric, which it does in terms of weight capacity. For cross section equivalence, it is 175.
OEM rims are 4.5" wide standard and the HDs are 5.5". The BFG web site has rim recommendations for tire sizes. I know for a fact that a 205/70 is too wide for the 4.5" wheel.
I agree with the recommendation to stay away from bias ply for a daily driver. I think a 195/75R-14 would be available in a whitewall and give good service on the narrower rim. (That's what I did with the 66 Dart.) If you must have bias ply tires, see the Coker tire web site. They have a bunch of the old Goodyear molds.