Wondering what some of you are running and what the 350 SBC recommended thermostat temp is?
The 1974 350 in the Catalina runs at steady 160 degrees after warming up.
Seems like that is too cool but have not run in anything above the high 70's
thinking about going to a new thermostat in the 180 to 195 range.
Appreciate your input based on what you are running.
Lost in the 60s said
Apr 30, 2022
"If it ain't broke, don't fix it".
I would leave it alone until you have run it in warmer temps to see if the rest of the cooling system keeps up. Is the fan mechanical, or electric ?
I, generally, run 180° thermostats, never 195°.
BLyke said
Apr 30, 2022
It is a mechanical fan looks like the manual says 195
We were far more concerned about overheating in the White Elky and Biskwik,
more ambition than brains said
Apr 30, 2022
p.s.
Will probably run 195 stst in LT41956 project, as that one will be computer controlled, have high-capacity cooling, electric fans.
Too cool may affect performance slightly, too hot could be catastrophic.
180 degrees will still be pretty toasty on a warmed up carbureted vehicle.
Concern about adequate passenger heating would be unusual in the summer use of our cars.
Don't pretend to be a mechanic, however, think I am being practical.
Even with a 180 stat, white elky runs hotter than I like.
Hate antifreeze spewing out the overflow.
We may still swap out the clutch fan to verify the current one is working properly.
Karl
Derek69SS said
May 2, 2022
Karl, on your LT1 with reverse-flow cooling you can go colder on the Tstat because the heads are cooled before the block, so your oil temps will be higher. I'd run a 160 in that, and bypass the coolant line through the throttle-body also. Modern engines run hotter just to burn cleaner for emissions... stock LT1 fans don't turn on until I think 220 primary and 230 secondary. I hate to run them that hot.
Old Gen1 SBC I'd run 180.
Newer reverse-flow I'd run 160.
BLyke said
May 2, 2022
thanks Guys
more ambition than brains said
May 2, 2022
Thanks for the advice, makes sense.
Not trying to hijack post, however, sounds like we all agree on running the older stuff way cooler. 180 degrees makes sense.
I will definitely run the LT-4 per your suggestion. 1956LT4 project will have custom designed cooling and A/C module.
Thinking based on their limited use our cars leave a really small carbon footprint.
Karl
Enganeer said
May 2, 2022
180°F is a good balance for cast iron. I tried a 160°F T-stat on my 400sbc that has over 10.4:1 compression with iron heads (good dynamic compression ratio and tight quench) and reverse flow serpentine setup and it just ran too cold for a streetable temperament. Switched it up to a 180°F T-stat and it seemed very happy (counter intuitive at first for that much compression). Swapped out to a roller cam with less duration but more lift and got even better. Switching to Holley TBI helped even more as I could dial in fuel ratios, timing, knock sensors. electric fan controls, etc...
Don't forget to drill a small hole in the T-stat to help with to help bleed air out the system...the take away I hear it will run about 5 degrees cooler than rated.
Karl,
If you still running a stockish LT-4 and computer, don't be afraid to stick with around 190°-195°. Aluminum in general is so much better at heat transfer than cast iron to your oil/cooling system. You can play with lower temps T-stats but you may need to optimize the settings to realize the gains via a tuner. How much gain depends on your mods.
more ambition than brains said
May 3, 2022
Good to hear from you John. Hope all is well with you! Karl
BLyke said
May 4, 2022
"180°F is a good balance for cast iron. I tried a 160°F T-stat on my 400sbc that has over 10.4:1 compression with iron heads (good dynamic compression ratio and tight quench) and reverse flow serpentine setup and it just ran too cold for a streetable temperament. Switched it up to a 180°F T-stat and it seemed very happy (counter intuitive at first for that much compression)."
Thanks, this is a fairly mild 350 and think I will change it out, the Old Pontiac radiator seems to be pretty big compared to my 71 Chevelle
Wondering what some of you are running and what the 350 SBC recommended thermostat temp is?
The 1974 350 in the Catalina runs at steady 160 degrees after warming up.
Seems like that is too cool but have not run in anything above the high 70's
thinking about going to a new thermostat in the 180 to 195 range.
Appreciate your input based on what you are running.
I would leave it alone until you have run it in warmer temps to see if the rest of the cooling system keeps up. Is the fan mechanical, or electric ?
I, generally, run 180° thermostats, never 195°.
It is a mechanical fan
looks like the manual says 195
Agree on the 180 degree.
We were far more concerned about overheating in the White Elky and Biskwik,
Will probably run 195 stst in LT41956 project, as that one will be computer controlled, have high-capacity cooling, electric fans.
Too cool may affect performance slightly, too hot could be catastrophic.
180 degrees will still be pretty toasty on a warmed up carbureted vehicle.
Concern about adequate passenger heating would be unusual in the summer use of our cars.
Don't pretend to be a mechanic, however, think I am being practical.
Even with a 180 stat, white elky runs hotter than I like.
Hate antifreeze spewing out the overflow.
We may still swap out the clutch fan to verify the current one is working properly.
Karl
Old Gen1 SBC I'd run 180.
Newer reverse-flow I'd run 160.
Thanks for the advice, makes sense.
Not trying to hijack post, however, sounds like we all agree on running the older stuff way cooler. 180 degrees makes sense.
I will definitely run the LT-4 per your suggestion.
1956LT4 project will have custom designed cooling and A/C module.
Thinking based on their limited use our cars leave a really small carbon footprint.
Karl
Don't forget to drill a small hole in the T-stat to help with to help bleed air out the system...the take away I hear it will run about 5 degrees cooler than rated.
Karl,
If you still running a stockish LT-4 and computer, don't be afraid to stick with around 190°-195°. Aluminum in general is so much better at heat transfer than cast iron to your oil/cooling system. You can play with lower temps T-stats but you may need to optimize the settings to realize the gains via a tuner. How much gain depends on your mods.
Good to hear from you John.
Hope all is well with you!
Karl
Thanks, this is a fairly mild 350 and think I will change it out, the Old Pontiac radiator seems to be pretty big compared to my 71 Chevelle