340 tooooo hot
We get many similar calls on our tech line looking for a 31" radiator, our biggest!
Out of the 10 calls we get on overheating, 9 are usually not cooling capacity issues but Ignition timing and fuel metering issues.
Most of the time these issues are corrected with a $69.00 distributor recurve rather than a $300-400 radiator to cover it up.
It's explained in my book but just to touch over the topic....If the fuel doesn't have time to burn completely (Not Enough Timing) or the A/F ratio is excessively rich then the unburned fuel will be forced out the exhaust valve while it's still burning. Or in a case of excessively rich A/F ratio where the oxygen is consumed and unburned fuel is left over, as soon as it hits the exhaust runner and any oxygen is present it will re-ignite, either condition will create a blow-torch effect in the exhaust runner and overheat the head no matter what radiator you have. Even if you manage to put enough cooling capacity on the engine to keep it cool, it's only bad-aiding a bad tune-up.
"I go through 3 sets of header gaskets every summer, I need a better gasket" you wouldn't believe how many time I hear that statement.
"I hate my TTI headers the Ceramic coating turns dull gray everytime I drive the car" another tell tale of tuning issues, Ceramic coatings will turn dull at about 1380*F EGT, a street car should be around 900-1250 max, race cars should run around 1050 to 1300. Of course if you ask 10 crew chiefs in NASCAR or NHRA Pro-Stock you'll get 10 different answers as each crew chief may be looking at a little different tune-up that he prefers, who's right? I don't know, I find my rule of thumb IMO adds to engine life and driveability.
Of course an adaquate radiator, fan system and a clean cooling system are also important.
You read more about our book on our website