454 Mag stroked to 496 w/ProcCharge what carb
 

Winter project trying to get finished buliding 454 stroke to 496 run 8.7:1 comp, Bob Madara cam, 781 heads with work, inconel valves port polish, Question is what size carb. I have been told to go smaller blow thru like 450 cfm I currnetly have 850 but told to much carb and would not work.(Run Lean) My thinking is i need more since pushing air 3.5 boost. M3sc procharger

Any thoughts, sorry if I left any info out,