Will,
To everyone I regret the thread hijack.Will length on our Pport runners is best between 20 and 22". At least in that state of tune. The larger ports will need to be shorter since they will make more power at higher RPM. Also note that 1-3/4" ports are not huge, the Car racers often use taller ports and even made rectangular but they will turn the drag racers above 10,000 RPM.
Bill