Cooling issues 69 Dart GTS 340

fan shroud?
water pump impeller slipping on shaft?
Fan shroud ...Yes
Water pump hasn't been off. But I can check that.
I have a 7.lb radiator cap on it.
Radiator has a new core and flows well.
At idle the temp keeps climbing Driving it will come down but not stay there. Saturday drove it for 20 miles eventually it climbed up to 215. when I parked it overflow hose spraying.

Thanks for all the replies. I'm going to pull water pump and check that.