need a lesson in A/C

well if the compressor and/or clutch is shot, repairing it looks to get pretty expensive. This is looking like probably $400-600 that i probably don't need to spend on an $1800 car... the clutch alone is $70, the compressor is 150-200. She's adding up quick...but if the compressor and clutch seem to work, maybe i'll give it a shot. also reading alot of aftermarket intake manifolds don't clear A/C which would pose a problem for wanting a 4150 flange efi system