On my '71 Dart Swinger, I had the stock rims widened to 7" and fitted 225/75 BFG radial TA's. That's really on the limit and a bit more, so my next set of rubbers will not be bigger than 215/75.
Yes you could get 245/60/14 under there but aren't the stock rims 4.5 or 5 wide? That would mean putting 9.5 inches of tire on a skinny rim. If you not really concerned with handling characteristics and want the eye candy thing, then go for it. If you are interested in better/best handling characteristics then I wouldn't put more than about 8 to 8.5 on a narrow rim like that.