I was really hoping to be able to keep the A/C on my L67 swap, but from what I've seen if you don't want the Alt to hit the decklid, your only option is to delete the A/C.
There are alt relocating brackets avail. that put it down near the axles. if you leave the alt on top you will need to "notch" the decklid. Do a search for 3800sc alt relocating
Isn't the A/C unit on the front of the engine? I have my alternator low mounted on the back of the engine. I don't have A/C, but I would think it could remain in the stock location if you move the alternator where mine is.
Everything on my 3800SC is in it's "Stock Location". Alt, AC, and Power steering and Coil pack. why not just Notch the deck lid rail ? Then you need NO "Adapters", NO "Special Mounts", no re- wiring.