Right Carb for my 340

Hello all. I was wondering what the A body group would suggest for my 340.
spec:
10.5:1 comp
509 lift 292 dur (purple shaft)
Eddy heads
M1 dual plane
4 spd
3.73 or 3.23 gears (depends where I am going)

I now have a 700 double pump and its going through fuel like nothing. I think like a lot of you men and women, I just want to be able to drive the car and get some sort of distance to a tank. What can I do? I figure I will start with the carb, the calculator on the web sits says 570-600 cfm for a 340.
What do you guys say?
If a small carb like a 600 cfm, what size jets so that I don't have a fuel problem?
Any suggestions will be appreciated, I thank you all in advance.

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