This is any interesting topic. I started my Pontiac Journey acting as ‘scrub nurse’ for my older brother and his best friend on the weekends while they worked on their Pontiacs. This was circa 1983. Back then, HO Racing and Nunzi were the only players at the table for aftermarket Pontiac Performance. And I remember both offering ‘cooling kits’ as an introductory upgrade that included 4-row factory style radiators and 160* T-Stats. My brother and his buddy both had 160* T-Stats in their cars - which ran notoriously ‘warm.’ Maybe the 160 stat was a crutch for an inefficient water pump? I will say, my brother’s car had quite a bit of compression for the street by today’s standards: 670 heads on a 428. There were no aluminum heads available back then. I believe his friend’s car was a ‘bit’ more pump-friendly with a set of heads from a 350 on his 400.
Fast forward - when I first got my Red 73, she got SO hot the first night I took her to a local cruise night that she literally vapor-locked and died right there in 4-lane traffic. I limped onto a side street, threw the hood, and sat for about a half and hour and then limped her the rest of the way to the event. By the time the sun went down (along with ambient temps) she ran fine - albeit pretty warm - all the way home. Of course, I did the kitchen sink routine: 4-row factory style radiator, Flow Kooler water pump and 160* stat. That car will run virtually dead on 160* (verified with a heat gun) form the coolest days in fall and early spring all the way up to the hottest day of summer that I’m willing to sit in a car with black vinyl interior and no AC. Point is, the current low-tech cooling system is incredibly reliable.
But I have often wondered if the car would run more efficiently at another 10* of operating temp? I just have never wanted to leap back into a 180* stat only to find that she pings and chugs after I turn the key off on a hot day. I always wished there was an option for a 170* stat rather than taking a 20* step to see what happens.
In reading this thread, I did a bit of a dive reading posts on other forums and I found a supplier who sells Custom in-house built 170* stats for virtually all makes including GM / Pontiac. If you back track from this link, there is a ton of info on this site about how coolant temp affects performance:
https://www.lethalperformance.com/re...hermostat.html