I run a 180 in my Dart and it always runs its best ET when i leave the line at 190.I will turn the fan off sometimes in the water box to make it heat up to 190 if its not much of a line in the staging lanes.Time slips dont lie .Back to back runs it will pick up .04-.05 in the 1/8 at 190 over 180 (as i have tested it many times).On a street car i run a 160 ...

195 other then dead of summer then 180

if your running a car new than 92 ish it might have an aluminum radiator. however like the cuda in the picture it would be pertinant to ask if its an copper radiator or a newer aluminum style radiator. as your explaination from griffin would be related to a modern aluminum...
also some engines are reverse flow to heads first then to block to radiator.
next would be to assume the radiator in the vehicle is of appropriate size and or the fan is efficient.
if the cooling hardware being employed is not sufficient than you will get heat soak if your not running a t-stat
lots of cars have old copper radiators that fit the chassis from the factory .then they for example put a big block in a car that has a small block sized radiator.
or over bore cyl walls that factors in..or raise compression..
not to exclude running alcohol as fuel that is a factor as it runs cooler

the griffin example as i read it refers to their radiators...which are more modern aluminum and most often oversized..
so all things being equal i would still stand on my conviction...
heat soak can be a factor with out a t-stat or even with a t-stat if the system isnt sized properly or efficient for the application

not knowing these things and making an judgement would be an assumption

and at this point we are still ignoring the whole premise to his question..which is what is a good,adequate or best temp to maintain for his application..the only way to maintain a constant temp is with a t-stat..
i might say..if its an iron head iron block
id go 175-180 depending on carb or carbs.
if its a high compression or supercharged i might say 160 or if your at high elevation ..
if its aluminum headed i might say go with 185 or 195 ..
ditto if its an alcohol fuel.

I was just wondering the same thing. The 1971 Chrysler service manual says the thermostat should be 185 degrees. But Napa, AutoZone and O'Reilly's only carry 160, 180, and 195. They all claim 195 is OEM temp., but not according to my manual. For a nearly stock 318 motor, think its better to run 180 because that's closest to 185, or run 195 because a little hotter is better than colder?

If we're talking about at what point a motor would start to allow blow-by past the rings, and just basically be "worn out", Is it safe to assume that the difference we're looking at is the 180* motor goes 130k - 150k miles, while the 160* motor maybe showing the same wear by 100k. (???)

Most posters in this forum are asking about hobby type motors that are in weekend cars, and would take 50 years to see 100k mi. I doubt the wear issue is a factor in these discussions.

I run a 160 stat in my car because I've seen evidence at the strip that tells me it makes more power there than it does at 180. Also, with a 160 stat, if I get stuck in traffic (or idling through the staging lanes) on a hot day and my temp climbs, It takes a while to get to 200. If I start at 180 and get stuck in the same traffic, It's a much shorter window I have before its at 200.