440RB INDY DUEL PLANE OR RPM INTAKE HELP

There are no benefits to single plane for your service requirements even with that size of engine unless you wish to reduce the amount of torque you have at lower rpms. I've done dyno tests on this size engine with the RPM manifold and the Victor single plane. With the gasket matched RPM manifold vs the gasket matched Victor you will gain as much as 40 LB-FT at lower rpm's and lose maybe 15 HP at 6,000 rpm.