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RIP (12/27/60-7/18/15)
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767 Posts
Discussion Starter #1
I see there are 3 different temp of thermsotats available.
er...................recommendations?
thanks as always
 

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64-67 Expert
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8,569 Posts
No. The lower temp 'stats open up at lower temps. That's pretty much it. If a car is going to run hot and detonate, it will do it with a 160, 180, or 195 T'stat. T sat doesn't dictate how hot a car will run, the cooling system does. I've had Toyota's with such efficient cooling systems, that the T stat's would cycle open and closed... Here's my take on it: Early GTO's run best a 160-180 degrees. I had the '65 out yesterday, and it was in the mid-high 60's. The car never got to 180. It got up to 175. Coming home last night, the temps were in the high 30's....the car ran at 170-175. The heater/defroster was nice and toasty, and it ran great. Why would you want a Pontiac to run at 180-195 out of the gate and potentially ping and knock? I'm in the same boat as you, Ruk...I've got the original heads and am running a lot of compression. I need to run boosted gas anyway. With a Pontiac, heat is your enemy when it comes to pinging. BTW, this car used to run 220 all the time until I clearanced the water pump, installed a 19.5 inch fan with HD clutch, and a fan shroud. What a difference!! With the '64-'67 combustion chambers, (closed bathtub configuration) these engines are Ping Monsters when they get over 200-210 degrees. Hotter engines are more thermally efficient (new cars run 220 all the time), but with our od dinsaurs, a cooler engine is better.
 

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Super Moderator
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5,751 Posts
:agree What GeeTee said...

A hotter engine (hotter combustion chambers) will have more tendency to detonate. Honestly though, unless you've REALLY beefed up the rest of the cooling system, these things are going to tend to run 180, 190 or better even if you put a cooler t-stat in them. It'll just stay open all the time.

Bear
 
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