Best spot for water temp gauge

[565bbchevy]

83MONTESS if you use the spacer and run a thermostat then it has to sit on top of the spacer otherwise it will bypass so much water the thermostat will not open.
Ebay has a few under "Chevy water neck spacer" but if you are going to use a thermostat look for one that has a recess for the thermostat.

 

[Longroof79]

I have my temp sensor mounted in the cast iron water neck. I've run it that way for years using a mechanical gauge, and now using an electric gauge.