I Replaced the Heads and Don't Remember This
 

I recently replaced the heads on my 86 G20 with the 5.7L 350, and I've got everything put back together for the most part. I kept a journal of everything I disconnected or moved in order so I could do the same things in reverse. The journal got soaked however, so there has been a lot of Haynes/Chilton and forums usage to try and retrace my steps. My question now is what is this? Is this a coolant temp sensor?
https://cimg7.ibsrv.net/gimg/chevrol...38b80af076.jpg
And I have a vague memory of this going straight into the passenger side head. Does this look like the correct spot, the flush bolt in between the two head bolts?
https://cimg2.ibsrv.net/gimg/chevrol...cab12fdaed.jpg
Thanks!

try the drivers side head

It's a mirror image but the wire won't reach where the flush bolt is. Between the number 1 and 3 cylinder.

missed the part where you siad you replaced the heads. yes thats the CTS and yes the heads are mirror images, take the plug out of the passengers side head and put the sensor in, you prob want to use some sort of sealant thats meant for high temps. i used a paste on my cummins and ive used tape with no issue but many say not to use tape. im used to working on trucks and on trucks the CTS is in the drivers side head but im guessing vans are a little different

Awesome, thanks!