I want to buy a 1979 F350 Lariat with 70,000, asking price $4,850. It is currently registered and passed CA smog a month ago. My mechanic said it is not a good buy because it will probably fail smog the next time around. If I want an older truck, his advice is to purchase one pre 1974 so there is not smog required. Do you have any advice and is there a site that shows likelihood of that specific truck not passing?

Thank you.