whats the difference?
 

https://cimg7.ibsrv.net/gimg/dodgefo...01f36d037b.jpg
Whats the difference. I have 4.7l 2000 is one ac and non ac?

I don't know what the difference is, but if you are trying to figure out which one to buy just go measure your tensioner pulley to check. 76mm = 3" 90mm = 3.5"

There used to be this MOPAR site i ordered parts from it was a dealer some where up in New York trying to find it as well as the chart that shows you how to read your glove box tag that tells you what all you have; thought for sure it was a post here somewhere in the forums but i cant find half of nothing I used to use when i had my previous dakota.

Measuring it might just be the way to go anyways. lol

Jon, there are lots of Mopar sites. Just plug in your Vin and act like you're ordering the part, then get the OEM part number. It should more or less match up with one of the parts you listed above.