automatic to manual swap for 85 chevy

[85chevy]

I just got an 85 chevy and was wondering how hard it would be to change the automatic out. I like a manual better and I have a 91 firebird with a 5 speed already. I know the whole thing will be a pain but it ought to help with gas mileage and be more fun. If I did go ahead with the swap should I even bother with the hydraulic clutch in the firebird or would I be better off looking for a mechanical clutch? I don't have a whole lot of experiance with transmissions so any help would be appreciated.