O2 Sensor For My 91 Silverado

[2004GMC1500CC]

Well, it's time for the annual crap shoot that is my emissions testing here in Texas. Every year my 91 passes, but some years are more expensive than others.

 

I only drive my 91 ~ 1000 miles a year now, mostly on bad weather days, so I don't REALLY mind doing what it takes to pass, but it would be nice to not have to worry about it.

 

The truck is a 91 Silverado with a GM crate replacement 5.7L with about 25k miles on it. I bought it used like this from a friend. The truck has ~260k on it and runs great, but the former owner lived in a county with no emissions on it. He put on long tube headers, with true duals. It has dual cats on it and a single O2 sensor. I think that the O2 sensor is too far away from the motor with the long tubes on it and would like to replace the 1 wire unheated O2 with a 3 wire (heated) O2 sensor. Is this as simple as providing 12V and a ground and splicing the 3rd wire in? Does the 12V need to be a switched source?