Of all the 216 and 235 engines ive built and swapped out and heads iv switched, the temp bulb goes in the top of the head,as described above.
On some, i've had to use a special adapter,not just a reducer.
The adapter has a "shoulder" about halfway down, inside for the bulb flange to seat against.
I have the part right here in front of me if someone can post a pic.,,i'll send it to you.
Marty
