Can anyone tell me the original factory spec. temperature for the thermostat on a '67 400. I'm getting conflicting info from the Parts companies. Thanks.

I don't know the factory spec but 190 works the best.
Jim

Would'nt a lower temp. t-stat be better.
I put a 160 in my 68'

from pontiac parts manual on 1968firebird.org
"66-72 All...3027868... ..........
Thermostat (195 degree)"

the service manual on that site states 190* more than once.

Doug,
Believe it or not 160 is too low. The engine is designed to run warmer than that.
Jim

190 thermostat is not available in the parts catalogs. They have a 180 or 195 to select from. Wouldn't the 180 be better?

195 is stock.

I tried a 190 and it didn't work for my setup, allowed the block to get too hot and then it was just a never-ending game to catch up to that heat and cool it down. Stuck with a 180 and all is well for now. ALWAYS looking at that frigging temp gage though!!!! :rolleyes:

I ran a 160 in the 326 that I had in my bird.
Never any problems
I'm going to try a 160 in the 400 also.

If you have an adequate cooling system and it's not blistering hot out a 160 thermostat will keep your engine at 160 degrees. You will not attain peak performance at this temperature.
Jim

I went with a 180 and didn't really have any problems unless, stuck in traffic and there was no movement. then I would be a temp gauge watcher.
Wade

One important thing to remember is that "open thermostats are all the same" no matter what temp they are. Once you reach whatever temp they are set for you have full flow. So, if you are at 195 degrees, your engine can't tell the difference between a 160, 180, 190 or 195.
Jim