AVS2 carb tuning. Anyone with experience out there?

On another note, is this 650 big enough for my 340? I do have an new 800 cfm AVS sitting on the shelf I could try but I really think the 650 should be sufficient for this engine.
Yes the 650 is big enough. If you can't get the 650 to work right . then I suspect you will have even more trouble with the bigger carb.

I would tighten up the air door two full turns and see what happens

now; What's your TC stall and what gears and I assume you have an A-body, but which one?
Can you give an idea of cam and cylinder pressure. Oh wait I see you said 73 340 and stock type Comp cam. Is it this one?
Brand: COMP Cams

Manufacturer's Part Number: 20-212-2

Part Type: Camshafts

Product Line: COMP Cams High Energy Camshafts

Summit Racing Part Number: CCA-20-212-2


UPC: 036584500124

Cam Style: Hydraulic flat tappet

Basic Operating RPM Range: 1,500-5,500

Intake Duration at 050 inch Lift: 218

Exhaust Duration at 050 inch Lift: 218

Duration at 050 inch Lift: 218 int./218 exh.

Advertised Intake Duration: 268

Advertised Exhaust Duration: 268

Advertised Duration: 268 int./268 exh.

Intake Valve Lift with Factory Rocker Arm Ratio: 0.454 in.

Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.454 in.

Valve Lift with Factory Rocker Arm Ratio: 0.454 int./0.454 exh.

Lobe Separation (degrees): 110

Computer-Controlled Compatible: No

Grind Number: CRS 268H-10

If yes then I suspect your cylinder pressure is gonna be in the basement, so your combo is gonna need some help from stall and/or/together-with rear gears