Ok, first the carburetor being used should NOT affect the engine temperature, assuming that it is providing the correct air/fuel ratio.
Now, I believe that if your running lean, the engine will create more heat?? Richer less heat, but worse fuel economy fouling of plugs, etc. I think?? But the radiator system and thermostat should still maintain whatever the thermostat calls for if not then the radiator and fan combo aren't big enough for your application. If changing carbs then your obviously changing the air/fuel mixture.
Back in the 60's and 70's the cooling capacity wasn't always up to the big engines heat capability. Especially, when your running larger carbs without modifying the jets. Remember, you can put on a bigger carb, which has jets designed for maximum air flow, but the engine doesnt change so typically the larger carb will run richer, and produce less heat, but, way worse gas economy, and very little extra power. Heck i think the original 383's came with only a 500 cfm carb, so putting bigger carbs on can change the air/fuel ration negatively as far as heat output or vice versa.