So I'm rebuilding the 305 in my 87 IROC and I'm a dumb*** I forgot to mark a sensor and now I can't remember nor figure out where the hell it goes. I'll post a pick of the sensor later tonight, but it has the same male end as the knock sensor on the passengers side, the sensor is on the passengers side. It comes off the section of the wireharness that has my throttle possition sensor and other throttlebody and intake sensors on it, all I know is that it's near mt knock sensor and starter, but I can't figure out where. Any help is much appreciated!!

 

Probably the secondary fan switch, goes in the passenger side head, right behind the exhaust port for cylinder 6.

 

Correct

 

I thought that's where the second CHT(cylinder head temperature) sensor went.... But I guess I'm wrong.

 

There has only been one engine temperature sensor- gauge only (in driver side cylinder head.)
The coolant Temperature sensor is solely for the ECM because it's more accurate and representative of cylinder temperature - located front of intake manifold.
The passenger side cylinder head temperature sensor as has been said is a non computer controlled Heavy Duty Coolant fan with a fixed on temperature setting.