Sure, here are my opinions,
1- different wheels, first figure out what you have and if they're OK, most are.
http://www.stovebolt.com/techtips/wheels/2- Brakes, work great for a stock truck if kept in good order. safety can be increased by adding a dual circuit MC in place of the single circuit original.
3- 216 and early 235's have a low pressure oil system, the rods have dippers to get oil. This system is OK but given how easy a later 235 or 261 swaps it makes sense to do that for the upgrade. In my opinion unless you are doing a complete and original in every detail restoration a 216 is not worth keeping. Basically run one if you have it but don't go looking for one or rebuild one.
4- I don't have any advice on automatic transmissions. But I doubt it's worth it for a 216 and probably not so simple or worth it for a 235 either, I don't know.
5- I suggest a diesel, well I'm OK with either basically stock (235 or 261) or a diesel, I don't care at all to see V8's in these old trucks. That said do what makes you happy
6- I've recently researched AC (as well as several years ago) I think Vintage Air is the best place to go for the kit. I'll be doing that myself in the next several months.
http://www.vintageair.com/keep in mind that the more you change the more you have to change to make the first stuff work out. More power needs better gears to use it, better gears give you more speed, speed needs better brakes, better brakes might need a booster, a (hydro)booster needs a PS pump, a PS pump is good for power steering and so on goes the list. Figure a lot of that out before you start so you'll know what you're getting into or not.
Good luck,
Grigg
