All I am going to say here guys, is take a lot of this "expert" advice with a grain of salt. Some of this stuff makes me roll my eyes, some of it makes me break out in laughter. Here's a hint.. I recommend that unless my customers live in a cold climate, and drive their car regularly under 50* ambient temp, that they run no thermostat at all, or just a restrictor if they find they need to slow down the coolant. Most GS's don't need a restriction to operate at 160-180 under normal summertime conditions. JW
Used to run no t-stat in the 70's. Was my daily driver in MI winters,(SS Nova) had different heights of cardboard to put in front of the radiator on cold days to get more heat. Headers would not hold the heat like iron manifolds would.