67 BARRACUDA SPARE TIRE SIZE

Original bias ply tires had very flat side walls. Todays radial tire is too fat. There are space saver tires that will bead up on the OEM wheel and fit in the well. Just example... 1 New Kumho (121) Original Equipment - T105/70d14 Tires 1057014 105 70 14 | eBay
You might find a decent one in a parts yard. Pray that you never need to use the OEM bumper jack. It hardly has a hook.