Intake differences?

DGC, I have found the air-gap to work better with a warm up period of 3 - 5 min.'s over a regular water heated intakes time. It's just when I used the air-gap, the engine acted like a big block requireing alittle more time to operate at it's best.
Your 3 mile drive into town in the cold is about the amount of time I allow the engine to warm up and another bit of time for the air-gap to work as well. (As in smooth idle and operation.)

From time to time when I did drive in the cold, the carb would regress back into a higher idle. Something got a chill. He he he.