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Discussion Starter · #1 ·
Just put newly rebuilt with bore, new cam, etc 289 back in my '66. Seems to be running hotter than before. Does a built motor normally run hotter? Got a 195 thermastat so I guess I'll try 180 then 160 if that doesn't work. Just wondered what normal operating temperature should be for 289? Also, how much does temperature effect performance?:headscratch:
 

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If you have a 195 ( I would use a 180 myself ) and your engine is running hotter than that, putting a 180 in will not bring the temperature down. If your cooling system can't maintain 195, it won't maintain lower. I think optimal temp for a 289 is around 180 for making power. But sounds like you have some cooling issues to check out. A fresh engine may run warmer for a very short while but not too long. I just put a fresh rebuilt 289 in my 67 and other than being slightly warm during the cam break in no issues. I did have the advantage of outside temps being in the low 40s at the time.
 

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joel is right. a new engine will run a little warmer, all thing being equal. put the 180 stat in it and should be fine.:bigthumbsup
 

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The Ford supplied thermostats were usually 192F which they claimed minimized engine wear. Running an engine too cold, or hot isn't good for it.
 

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I think the 190+ thermostat specification really came from California emissions requirements. Making a 289 pass those requirements really was kludge attempt and make the engines run really bad and much less efficient.
 

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Discussion Starter · #6 ·
thanks for the input ... put the 180 in and temperature dropped to an acceptable range.... only have 200 miles on it ....new high performance water pump, new radiator, all new hoses and just dumped the first break in oil for some mobile 1 synthetic :bigthumbsup
 

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thanks for the input ... put the 180 in and temperature dropped to an acceptable range.... only have 200 miles on it ....new high performance water pump, new radiator, all new hoses and just dumped the first break in oil for some mobile 1 synthetic :bigthumbsup
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180 is the standard one most people use. Remember, if your running hot .. Check the timing .
 
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