Narrow band come in three flavors-

Single wire = output with ground through shell

3 wire = output with 12V and ground for heating element, sensor still grounds through shell.

4 wire = output with 12V and ground for heating element, sensor grounds through 4th wire.

Most gauges have sensor input, ground and lead for dash lights.

All the carb cars I have done use a 3 wire sensor installed down in the header collector. Being heated they warm up in 10 seconds flat and you don't have to worry about them getting sleepy if idling for extended period of time.

3 wire were used by mamopar from late 87 to early 89.