Problem identifying part

So, awhile back my car took a dump on my head gaskets, and since im a noob, i had to take it to mechanic. He replaced my head gaskets, a bunch of other gaskets, some broken timing chain guides, and cleaned out and ground down my heads a bit. car ended up great, EXCEPT my A/C magically died (and he left me with some crappy exhaust leaks, but thats a whole nother story..). Anyways, i figured there was no freon in the system cuz it was pulled apart, so I proceeded to check the level (empty, of course) and added freon. The compressor kicked in, and everything seemed cool until one of my a/c lines friggin blew up and spewed the freon everywhere so afer a numerous set of "wtf's" and "omfg's" i went back to see the damage. turns out i need a new line, but i cant really identify which particular line it is.





its the line leading into the condensor, with a pressure switch and a valve, coming from the little canister situated near the a/c compressor. I tried looking for the line here in town, but apparently my particular year of mustang has two different variants, mine being the older and rarer one. So they tried charging me over $200 for the line they MIGHT have somewhere in wisconson anyways, sorry for the long post, but what line is that, and where could i find such a rare oem line? i THINK its the discharge line but im unsure. also, what would have caused the line to blow in the first place??? thanx yall :SNSign:

EDIT: i know, i know, my engines extremely dirty, but i cleaned it all up once, only to have it look the same 2 days later, i live in arizona and theres no way to avoid the dirt around here

bump