rpm and therm. ?

I'm running a 1976 350 engine and tranny and was wondering what rpms you guys are showing at 55-75 miles an hour? my thermostat this week has been going to 210-240 before opening up. Is this a sign that it's on
it's way out? Never had one do that before, they just usually don't open up then you overheat then maybe work for a little while then you know the deal! Let me know what you guys think. James
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thermos are cheap. If it was me, I'd spend $10 replacing the thermo and gasket, rather than risk the opinion of a bunch of internet "Experts" being wrong...
'course.. I'm just an "internet expert". Taking proactive action against a problem never hurt, though....

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Re: " I'm running a 1976 350 engine and tranny and was wondering what rpms you guys are showing at 55-75 miles an hour? my thermostat this week has been going to 210-240 before opening up. Is this a sign that it's on it's way out? Never had one do that before, they just usually don't open up then you overheat then maybe work for a little while then you know the deal! Let me know what you guys think. James" --------------------------------------------------------------- James,I'd replace the thermostat.It's a very easy operation.Get a 195 degree thermostat.Drain about 3 quarts of coolant from the radiator (there's a drain on the radiator on the side facing the engine,on the drivers side i think) remove the two bolts and give it a few taps and it will come off.clean off ALL the old gasket and put on a new one with the new thermo.Torque to 20-30 ft,lbs only.Replace coolant. As for the RPM question above,it depends on your differential gear ratio and your tire size.My truck runs 2500 at 60 MPH with 3.73 gears and 235/85/16 tires. Your RPMs with the same set-up would be a few hundred higher since mine is a stick.My diff has a metal tag on one of the bolts that lists the ratio,but there are other ways to find out.
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