Wheel, tire,offset?

What bolt pattern, what brakes, what rear axle, stock spring locations?

And what is the intended use of the car?

If you want to "fill the wheel wells" you could run 275/35/18's on all 4 corners if you wanted to, that would fill up ALL the wheel wells. But I'm guessing you were mostly talking about the rear wheel wells...
Switching to big bolt pattern, drums in the rear, stock spring location. Just a street screamer. Planning a little less tire in the front than the rear, in terms of width.
Assuming you are talking about a 67-69 Barracuda, still with 5 on 4 bolt pattern.
Pickings are pretty slim for 5 on 4, and not cheap. Basically Cragars, slots if you can find em, steelies for hubcaps, and rallyes.
Depending on your budget, there are 15x7s (and larger sizes) from Team III/ET wheels that look like torque thrusts, (beautiful, but LOTS of $$$) and 17x7s from Boyd Coddington, also tt lookalikes.
American Racing makes a centerline lookalike that Summit lists, but i dont know if they really are available.
If your car has been converted to 5 on 4 1/2, all this info is useless, we'd need more info about your car.