What size carby

Hi all, just wondering what size carby I should be running on my 340?
Engine mods are:
Ported Eddie heads, crane 1.6 rockers, Head flow numbers.
LIFT--IN/EX IN EX...
.600"--276.6/218.6 34.4 33
.650"--283.5/221.6 40.3 36
Manifold is a port matched victor junior 340, cam is a comp solid roller P/N XR286R.
Engine comp is 10.8.
I'm running a secondhand 850cfm race demon on it now that's been on it a little over 8 months. I think it's a bit worn out as it keeps going out of tune, so I'm going to treat myself and buy a new carby.
So I'm wondering what size carby will suit my engine?
The dyno pull was before I installed the 1.6 ratio rockers.

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