I have a A/F guage, so I need an 02 sensor. I've been told to get one from a '88'ish Mustang 5.0. It's the heated kind. Is that right?

Where is the best place to put the 02? Just in the header collector?

you dont neccesarly need a heated o2 for the air/fuel guage. if you are using long headers that extend to the firewall the heating part of the o2 is used to help heat the sensor ...for shorty headers a one wire will do just fine and i think all o2 sensors are threaded the same ive only seen one bung being sold for them and are put in the collector right where the header tubes come together..hope this cleans up some confusion for ya...