My car also had a 327 with A/C.
As was said by 68L30 "you will need a big block condenser box,moter mounts,and all the brackets to mount the compressor".
Also the B/B springs.
On a s/b, the neck on the evap. where the POA valve is attaches, curves to the fender side. On a B/B the poa valve is mounted on the engine side. I didn't know this until I bought a whole B/B system out of another 1st gen bird. Also when you are looking for parts the 1st gen Firebirds are interchangable. On the inside of the car the housing is different. If you need a # of a place for parts send me a message. Franks Pontiac in CA. sent me a whole setup.
The hoses will be the hardest thing to find. All the other parts are around.
Talk to Jim at: www.camaro1.com
Let him know "502 Bob" gave you the number. they are located in Ohio. 888-706-1188
Headers: Hedman #650016. From Summit $351.00.
They are tight, but they will fit.
Mine rests up against the evap. box but didnt burn a hole. The headers have the Hot jet coating on them.
Good luck with your project.
69 Blue 502
69 Coupe LeMans-Blue
Frame-Off Resto, ZZ-502/502 Crate, A/C, Griffin Rad., March Serpintine Sys., 2800 Stall with Hughes T-400, Currie 9" with 370 Gears.