Joe - I can't see those sills being correct, there can't be that much difference in frame width - my first thought was they're 67-72 sills, but the guy to check with is
Tony "4-5-6trucks", who has a lot of info about the 60's trucks [see the bottom of that page!] ... haven't noticed him around in awhile, but you could email him if someone else doesn't chime in here shortly
Bill
