Originally posted by catsasswiring
My opinion of your heating problem is a fuel/air issue. You need to make sure you have the right sized carburetor for the engine.
If engine runs lean it runs hotter. If carb. is correct, next you need to make sure the fuel/air adjustments at all four corners are set correctly. This is done by placing engine on diagnostic analyzer. Adjust air/fuel screws one at a time to obtain maximum vacuum, then go to next screw. This may take a few rounds to get them set identical. make sure you do not have any vacuum leaks on engine. Also, is carb. vacuum or mechanical secondary's. A big block with high HP, depending on cam shaft, will not have sufficient vacuum to open secondary's, that will again cause lean condition. A Dominator or Holley is the best carb. to use.
This is from experience!

Good luck,
catsasswiring

Your point about running the right size carb is correct, but an undersized or oversized carb doesn't mean the engine will run lean or rich.
It just means you need a larger or smaller carburetor.

A high horsepower engine in correct tune will pull a little more vacuum than a stocker.
To the tune of 1" or so of vacuum which is plenty to open the secondaries on a Holley that's functioning properly.

Even if the secondaries didn't open, the fuel/air ratio would still be ok.

The majority of the time overheating can be attributed to airflow problems with the radiator or timing issues.