Rob-
The ac compressor can be unbolted and hung from a support or laid on the
curbside fender liner without losing any R12 or damaging the system. I've
done this a number of times and a few years ago on my 82 Imperial when I
installed an Edlebrock intake manifold. (Note to purists: the factory EFI
was already long gone) I'd stay with the OEM compressor for a variety of
reasons.
Phil Brust
73 & 82 Imperial