How to choose a used engine??

Hi,

this weekend I found a interesting junkyard, not too far. Lots of old cars badly damage by time but with still lots of good stuff (in my novice eyes8-[ ).

Anyway, the guys as a couple of Diplomat/Caravelle, Fury with 318 and 360...so, if I look at the 318 I want 302 head. Is that right?

If I look for a complete 360, is there some years that I need to avoid?
If there is the "lean burn" system, can I use that motor with the carb/intake he has?
If I look for a 4bbl OEM intake and carb, is there some better then other?

Thanks