Matt167 is correct,,,,,you need to either rejet your carbs,,,or change your carbs to the correct CFM rating for your motor.

Originally posted by Matt167
If your getting to lean of a mixture because of to much air then, you could run a restrictor plate like the 1's that are used in Nascar, you could also rejet your carb and get the same effect, which, I would do. If your carb is too big ( CFM wise ) then, you could tweak the carb jets a little to get by, otherwise, a smaller carb is needed. The situation with your dual quad 450 CFM carbs, get 2 390 holley's and sell the 450's, if that's what's your asking. I'v never heard of too much airflow unless, what you mean, is too big a carb.