What style tire should I use for my Stock 1967 GT 390

If you have a Marti report, you'll know what it had when new. It's nearly certain that it had whitewalls, though. The WSW gives an illusion that the tire is lower and wider.

fwiw ... WSW tires were optional, so it's a good bet that the car had them -- particularly since it's a GT as the GT package included Wide-Oval Sports tires (F70 x 14 perhaps) .... the 205/70R14 should be a good size match .... however, there are variances among manufacturers wrt actual diameter of the tire ..... some vendors will quote a size for a modern equivalent tire but due to modern manufacturing processes, the new tire may not match the old, original one exactly ... case in point, I have an original F70x14 red-line as a "spare" (not that I would EVER use it for such purposes -- but it still holds pressure !!) and its diameter is less than a new tire from Coker ... I called Coker asked why the difference and they said its due to the over inflation process that's done to tire when it's popped from the mold -- so I don't know what the exact size should be, but the size you noted is at least in the ballpark .... good luck with the rest of your restoration and favor us with pictures if you're so inclined ....