Brake drum question

Up here I cant find 305-15s anymore. The last time they were in a catalog was about 2004. I had a search done the next year, at the tire shop were I was working at the time. Reply came back, disco'd,-none in Canada.
I have a set of 325/50-15s I occasionally run.They're drag radials tho, and street duty chews em up pretty quick. I put em on for show. I have to slow down for the corners a bit. I hate slowing down for corners!