*The door has crowbar damage? Yikes. That should not be too bad to find. You need to get a hinge rebuild kit too.
*There is an NOS (as in new old stock, original GM part in the box) on NastyZ for sale right now for $1000. How’s that, lol
*VIN will not show axle ratio. You can try to find the code on the axle tuber. Or pull he cover off & look.
http://www.nastyz28.com/camaro/camaro78.php
*you’ll need Z fenders too. 78 vents, scoop
*remember the intake is different from a q-jet vs a holly. (spread vs square bore). You might need an intake too if you go square bore
*if you can’t afford brakes, stop looking for the other stuff. Why can’t yours be resurfaced – why do you think you need new?
*to go t-tops you probably are bet off to change the whole roof section form a donor. The tops on these cars sucked good luck with that.
*to add AC to a non-ac car you need an aftermarket setup. You cannot put stock AC in it, firewalls are different. Budget $1000
*If covers don’t matter seats are not too hard to find. I threw a set away after not being able to give them away. Doors or trunk lids should be easy to find.
You drive this everyday and $$ is tight? Stop looking for everything and fix what you need to be safe & reliable then go from there. Been there, done that.