for your car there were small bolt pattern steelies, but 5 1/2 inches wide instead of 4 (like a rallye wheel). usually came with poverty caps (dog dishes, center caps). You'll have to ask here if they should be black or body color since I can never remember when they switched.
I believe a 1968 barracuda 318 car would have come standard with "4 1/2" inch (nominal size) steelies. The 340 for that year would have an option for "5 1/2" inch (nominal size) set of steelies.
