I have seen and did similar changes to a lot of 440 type motors with stock size intake ports, all of them slowed down in the 1/4 ET and MPH when decreasing the total CFM, regardless of intakes used I did a dyno test on my low deck stroker two winters ago, removed the six pak and replaced it with a 1050 dominator carb and intake, the motor lost 8 hp and had the exact same torque More CFM on a big block Mopar with stock type heads,ported or unported, makes more power in my opinion and experiences