I too would opt for the EPS intake or the RPM AirGap....These make alot of low end grunt...something you will really notice over the single plane unit....Also add a "Phenolic" 4-hole 1 inch spacer and you'll add a little more low-end to the mix....

As for cam....you make the most torque with a stock cam from idle with the heads you have... A bigger cam will make more torque but at higher rpm's....how high depends on how big you go....

I have had real good luck with 214-218 duration @.050 cam with stock spec's