Longer runners drop the resonant point lower in the rpm band.
With 40degC IAT and 248deg valve duration, a 26" runner will hit the 1st harmonic around 11000RPM, nowhere near 4500RPM! However, the 2nd harmonic will be around 5500RPM and a 3rd harmonic close to 3750RPM.
I've written some detailed (probably TOO detailed) responses about intake runner tuning, which can be found in a search: http://forums.hybridz.org/topic/105783-ideal-intake-runner-taper/