To take full advantage of the Ram Air effect you'll also want a large high flow filter,
and a modified throttle body too.
My Ram with a Fastman modified TB is now making significantly more HP all the way up to 5700 rpm,
and thats while strapped to a stationary dyno with no fan in the front.
No doubt it will be even higher when air gets rammed in at the track at speed.
My bud with nearly identical ram/mods has a stock TB and no feeder tube on his Volant and saw his HP drop off after 5200RPM