Wheels and tires combo

My 71 D100 is not A body so right now it has ramcharger steel wheels as I assumed is 15x7 tires is now 235/60/15 so the truck came with 16s as factory I am aware 16 rims are hard to find so i am looking for tire that fit in 15 and want narrow tires to make easy to steer any ideas that would be ??
It has slant 6 904 3.91 factory.