tires for my new 15x4 rims

You don't have many choices. If you have a 67 Barracuda, I would recommend staying at or under 26".

185-75R15 (25.9" Tall)
195-75R15 (26.5" Tall)

195-70R15 (25.7" Tall, This would be my choice.)
205-70R15 (26.3" Tall)