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i have built a 365 smallblock chevy with vortec heads, im guessing its around 10 to 1 compression. what thermostat should i use, a 195 or 180? i always used 195 but the motors were anywhere from 8 to1 to 9 to1 .
 

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runn141 said:
i have built a 365 smallblock chevy with vortec heads, im guessing its around 10 to 1 compression. what thermostat should i use, a 195 or 180? i always used 195 but the motors were anywhere from 8 to1 to 9 to1 .

I run 195* in everything. For ultimate power we know that colder does help gain 3-5 hp but I don't think that it is worth the difference in fuel mileage and engine wear for the average street machine.

If you can live with a 180 making heat from your heater..... then go for it.

It's a lot like compression ratios... You can build a 420 hp engne with a fuel problem or a 400 hp engine that will run on 87 octane... your choice.
There's about 3-4% difference for every full point of compression ratio, 9/1 vs. 10/1
 

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I agree, I run 195s in everything except LT1s with reverse cooling.

Detonation won't happen unless you have nucleate boiling or hot spots. If you have a properly operating cooling system, detonation shouldn't start happening until about 230*. That is of course ideal which we rarely see :)

I have run my non-aqueous caddy 500 cooling system all the way up to 260 without detonation because there was still effective heat transfer out of the chambers. No water = no boiling = full contact of the coolant to the water jacket. The downside to running a non-aqueous coolant is that it doesn't hold or transfer as much heat as water so its not as efficient.

The only benefit I can see to using a lower temp stat is power, but all other aspects of an engine's operation prefer higher temps... to a point obviously. Oil will be happier, better mileage, fewer carbon deposits, longer plug life are just a few of the benefits.

But, if you think about the 1800-2000 degrees that a typical combustion chamber sees at ignition, 15 more degrees of water temp won't alter detonation.
 
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