Help figuring out what to buy for Air Conditioning

I have a 1976 Dart swinger that came factory with no air. 318LA / Automatic
It now has a 360LA.
I live in florida and need AC and am not made of money so I need to get the solution right the first time around.
I am fine with an under dash universal kit but what specifically do I buy?
Can anybody help me as I do not have much experience with this stuff yet.

Thanks a ton.

SS