I think eleven number vins are pre 1973. My 1973 manual for Dodge motorhome chassis refers to a thirteen number vin. Who knows?? I have spent many hours on the search for things. Try to google VIN search and go from there narrowing down as you go.
Quite often I'm told that the chassis were purchased from the manufactures one or two years ahead of the actual build. You could check with some of the experts on this site, but I think vin numbers changed from whatever??? to thirteen numbers around this time. Good luck in your search.
