I was noticing how long it takes for my car to warm up and wondered if this tube on the header with nothing hooked to it is supposed to be used to help the car warm up? Its a small (mabye 3/8") U-shaped tube welded to the back primary on the pass. side. What is this supposed to be for?
The tube is welded there for your choke heat just like you suggested. Instead of the tubes that go to the cast exhaust manifolds, you run the lines thru this "U".
Howard
Yes, this is correct! The term for this 'tube' is called the heat riser and you use a fabric wrapped wire tube or a foil tube to connect it to your air cleaner unless you have the dress up kit then it will not work without heavy modification... but yes it is used to help your car warm up faster in cold weather!
That tube, if I am reading right, is for the choke. Since you have an electric choke, you don't need it.
To clarify what was posted above, choke heaters don't "warm the engine", they warm the choke spring assembly, and they attempt to do it at the same rate your engine is warming. That way the choke comes fully off once your engine is at operating temp.
There is really no way to make an engine warm up faster, other than to rebuild it with tighter clearances.