FWIW, '88 was when the 4.3/5.0/5.7 went to the roller cam. '96 is when they went to the Vortech heads on the v8s. I think the 4.3s were a few years earlier, maybe '94 for the Vortech heads.

On the rust, yeah I know... It is not worth it if there is any indication of rust starting. I am going to go look at the Dakota this week. I tend to crawl all over (and under!) vehicles when I buy, so I'll take a good look at the under side, brake/fuel lines, cab corners, rockers, doors, wheel openings, etc.