Both 2nd and 3rd gen shortbed have 103" wheelbase and 6' bed. Conclusion: the cab is not any longer between these generations.

So if a 2nd gen longbed and 3rd gen longbed both have 7' beds, but the former has a 112" wheelbase and the latter 122", where do those extra 10 inches go?

(It's hard to find numbers for 3rd gen longbeds, especially 4wd ones. Are they 7' 10" internally?)