I am replacing the stock carb on a 1978 350 with a Edelbrock Performer. The stock air filter has a snorkel with about a 2" opening, that also feeds air from a housing around the exhaust manifold. This stove is controlled by a vacuum thermostat. I know this is to "help combustion". The truck is 4x4 and is used during cold New England storms. How important is this heat feature, but what is the downside of the small opening to the snorkel? The question, to keep stock, or replace with a newer free flow style?