2000 Impala 3.4 Thermostat Housing torque Spec?

I need to replace the thermostat on this car. Anyone know what the torque specs are for the housing? Thanks...

Per my Chilton's manual . thermostat housing torque should be 18 ft. lbs. !

18 lbs x2

oddly enough, I could not get a torque wrench on it. So it's back to the "feels good enough" method. But it's on, not leaking and hopefully not to be done again for a long time!