Doesn't change the fact that if you have a 216 and you decide to do a test run on an engine stand, and you go to plug the water temp hole, (or you want to put an electric sensor in the hole) you have a problem because everything else on the engine is NPT and that one is UNF. Maybe what you could do is just stuff a cork in there? LOL! Or.. just wrap a 3/8" NPT plug about 50 times with teflon tape. Aftermarket came to GM's rescue on this one. Nothing a lathe and some special taps wouldn't resolve I suppose as the supply runs out.
Or screw in the stock gauge in the hole of the 216.
While I do enjoy your frequent outside-the-box thinking, many times the easiest solutions are actually inside the box.
Carl
