625cfm street demon

Hey everyone, I am new to this forum just wanted to know if anyone has tried the street demon 625cfm carb?
I just put one on my 340 and I have found that it seems lean. My engine is a 68 block with 71 J heads and tq intake with 71 340 exhaust manifolds and a comp cam 268xe . Any input or information would be great.
It's just a cruiser 5500 rpm . Already have the calibration kit.