I'm running 14 x 7s with 1½" positive back spacing & F70's on my '69. I have some clearance issues on the rear. Air shocks cured the problem. (The top pic is a bit deceiving. The car is sitting on a slight slope and makes it look like the rear is higher than it actually is.)
14 x 6s should give you plenty of room depending on your tire size.
As for caliper clearance, I have drums on the Nova but I've had these wheels on my Chevelle and they clear the stock calipers.
