65 mm throttle body
just replaced 97 5.0's mass air sensor with one from a Lincoln Mk 8 (about 80 mm) and throttle body with Ford Motorsport A302 65mm. Stock was a 58 mm model.
The mass air gives the most power increase, but you need to match the diameters of the mass air sensor and the throttle bodies closely, otherwise, you get a lean mixture warning (check engine light comes on). It runs kinda rough too. It runs well once these are matched.
The stock mass air sensor is large enough, and if you're going to change it, you need to keep your stock electronics connected - swap them over.
A Similar issue is at hand with the throttle body - usually intended for a Mustang. You can do a little machine work if you're able (and a little brave) in order to switch the throttle linkage - you need to use your current hardware.
So far, a good change.. Bill
In any event, it works great, makes bigger, smoother power