Asking a couple questions-will my A body corner?

Supershafts said
You can get plenty of different widths in 50's sidewall

I had 275-50-15's , 225-50 is narrow , i also used 265-60-15's, anything less than 265 is narrow

I'm looking for 255-50-15 can't find any . Only size I can find is 245-60-15 , would go 265 if they fit a 15x7 wheel and clear a stock 340 Swinger