^^^ Hmmm. Bigger diameter but shorter runners would really allow it to breathe while also raising where peak torque is made. In conjunction with a VVEL controller to maintain low speed torque with the new set up, this could really be an awesome NA mod...
I was playing with this calculator
http://www.wallaceracing.com/runnertorquecalc.php
Supposedly the engine makes peak torque at 5.2K RPM. Assuming the displacement is 225 ci (is that correct?), am I right that the stock IM has an Intake runner area around 2.21 sq inches and length around 16.15 inches long (from valve head to plenum).
If so, it would be cool to raise peak torque up around 6000 -- that would seriously raise peak power potnetial -- awesome for all out drag cars, but good for the street too, especially if VVEL can maintain low speed torque.
According to the calculator, for peak torque at 6K:
Optimum Intake runner area 2.55 square inches (calculated)
Optimum Intake Length 14.00 inches long (from valve head to plenum).