As said full exhaust, is alot different to just cat back. Using your current cat back and cat is a compromise compared to twin cats and a single 3" or twin 2.5". but can use with extractors ,like pacemakers (around 700 + more for ceramic coating + more if someone else is fitting).
Joe's mail order tunes start at about 200 I think .
Small cam package ( cam , collets, seals , springs, lifters, push rods and lube ) around 800 to 900. Roller rockers about 600 to 700 .
You'd also need gaskets, should do double row timing chain , harmonic balancer, run in oil , plugs , leads .
You'd also check condition of coil , dizzy , water pump, if these items are original or been on for along time sometimes easier to do it all at once instead of sometimes doing one of them 2 months later if your unlucky and it fails.
To get it dyno and road tuned at least 800+.
If auto will need stall converter if anything other than very small cam but you can't go too / very big as you'll need alot more supporting mods like higher compression .
I'd also get a cai like the hsv/ later ss one or a mace one .
Could get a 70mm throttle body. While manifold is off could get it extruded honed.
Other mods , for auto , shift kitted and second gear corvette servo cylinder, diff gears.
Those prices are ruff new figures, might be able to save shopping around or waiting for someones unwanted parts.