15X4 Race stars, tire options

The 68 Barracuda I bought had 15x4 and 15x8 Race Stars which are Summits generic version of the Pro Stars. The fronts have M/T 24.5 tires on them which is really to small and narrow for a street car, at least for me. So my question is, what are my tire options? I'd like a 26 " tall tire. Race Star doesn't make anything between 15x4 and 15x7. Any thoughts?