The other hose connection on the float chamber is for overflow. Take a hose off of it and run over the transfer case and down.
I believe it is normal for the inner cylinders to run richer so is probably fine.
Didn't you say you flushed the rad and it seemed fine?
It does sound like a blockage possibly though.
Might be worth sticking a hand in the heater box inlet beside the clutch pedal and try turning the plastic barrel fan to see if it's caught up.