Hey Brian!

I don't have any experience with that, but I found a few things that might be helpful:

P0420 DTC Code - Catalyst System Efficiency Below Threshold (Bank 1)
https://www.ford-trucks.com/forums/6...ode-p0420.html
https://www.ford-trucks.com/forums/3...ode-p0420.html
P0420 Cut off cats? - F150online Forums

Seems like more often than not it's the cat and not the sensor.