318 engine overheating

Ricardo said

Thank you for your information, about the poor quality of fuel I understand, could you clarify more about the problem related to the Holley 600 carb. The problem is about the mechanical secondary or jets ?

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The 600's are a small carb compared to the double pumpers which have overhanging float bowls. (the overhanging fuel bowls stay cooler and help the fuel from heating and vaporizing causing rough running issues) Edelbrock carbs are effected by the heat as well. Even more so than Holleys are. The fuel bowls are in the base of the carb and directly over the hot intake manifold. Ethanol blended fuels can boil at temps as low as 130° f or less.
You can help under hood and engine temps with a cooler thermostat if that will help and by blocking off the heat passage running through your intake. I would start there first.