I didn't have max ports on my stage VI heads, but switching from a 4150 intake and holley 850 to a 4500 M1 and a Carb Shop 1050 Dominator netted me nearly 4mph. I was running the Ultradyne NF69 mech cam .640 lift and had my shift light set at 5800. I always had good 1/8th mile times, but it seemed A LOT of cars would drive around me on the top end. That changed with the intake/carb swap. It increased airflow so much I had to drop from a 4.56 gear down to a 4.10 to manage the rpms...... and it went quicker yet with the 4.10.