Just for fun I assumed your Camaro at 250lb heavier than my Nova, so my guess is 3320lb including driver. If you can weigh the car see how that compares...

So here is what the Gonkulator thinks:
Bone stock
Torq 229 at 2500
Powr 153 at 3800
2.71
11.78 at 60.2
18.40 at 73.4

Langdons and your exhaust
Torq 234 at 2500
Powr 159 at 3900
2.66
11.52 at 61.7
17.96 at 75.8

Clifford and 390 Holley 4bbl
Torq 226 at 2800
Powr 177 at 4500
2.69
11.53 at 63.1
17.89 at 76.6
The Clifford is too big with that tall Powerglide+3.08 gear.
Not to worry, the lump port head will make up for it.
I'd be careful not to over-cam though if you are keeping the Powerglide and tall gears. Assuming you have 3.08's

I Gonkulated 1 final run adding the lump head, 9.5 compression, and a 194-204-112-.464-.490 cam.
Torq 259 at 3400
Powr 228 at 5200
2.62
11.00 at 68.3
16.87 at 82.7
Finally in the 16s!
Back in the 60s there were big-block cars in the 16s at 80 & change (and powerglide GTO's in the 15s for that matter!)
Not much will help that 60ft given all the tall gears but the small cam means it will still be a good cruiser and good on gas too. Good enough til the turbo arrives.