Everything matches:1989, FORD E-150, L6-4.9L, even the sensor looks exactly the same, only the new sensor has three wires and the old sensor has 4 and it is connected to 4 wires. Is there a simple trick around this?

The old connection.

 

Your post states a 1989 E150 while your public profile shows a 1990. When I looked up the o2 sensor for 1989, all rock auto lists is a 3 white sensor but if you look up a 1990, it uses a 4 wire sensor.
https://www.rockauto.com/en/catalog/...2)+sensor,5132

 

The "technique" used to splice this sensor into the wiring harness is a complete joke---such connections should be made using crimp terminals of the heat shrinkable types.