Single or Dual plane?

For my 408, which will be 11.9 compression, eddy heads, 244/[email protected] solid with 540 lift,
3.91 gears, 3000 converter and 750 mech sec. I am aiming for 6000-6200 trap rpm and about 450 hp @ 5800' altitude. The rpm air gap works well on the 360 and 318 engines I have had in this car, I am aiming for 11's up here in the stratosphere with the 408.