maybe you should try the lunati hydraulic flat cam. the one im running in my 406 is
part number# 638-00010LK (on jegs)
Adv. Duration: 292°/292°
Gross Lift: .480''/.480''
RPM Range: 2000-6000

Its a bracket master II designed for great power throughout the RPM range. very streetable.

I'm using the combo off of Chevy Hi performance, and they got 525 ft/lb torque and 425 HP out of the 406. They used the edelbrock rpm air gap, and vortecs. Im using all the same stuff.
Maybe this will help