What were the letter codes next the the racing # that traditional hot rods ran in the 40's I know it has something to do with class but not sure. I searched a couple key words and i couldnt find anything.
Engine size, then class. A/R would have an A designating the largest engine (at that time, now they have AA) R would designate roadster. Later on it went to A/SR with the S designating street. Take a look at the SCTA site. They may explain it there, but best bet is to get one of their rulebooks. Same goes for NHRA far as the numbering goes. One