Have a 200 74 Maverick redoing for my wife. There are 2 tubes coming off the exhaust manifold. One is going to the choke, this tube has two holes in it. What are my opitions. Is there any of these available? What about electric choke? Do the holes make a difference? What is the other tube for, I believe this is a heat tube as well.
One goes to the choke and the other draws fresh air from the air filter. Both can be replaced with ¼" copper tubing. This can be purchased at any hardware store. Make sure to be careful with the asbestos wrapping and reuse it on the new pipes. It is an insulator for proper heat transfer.
The one that does not go to the choke is in good condition it looks like it has a rubber line that attaches to it. Is that correct? You say it goes to the Air Filter?
Yes. Lift off your air filter and there should be a little nipple on the bottom that the hose goes on.
It was done because the earlier cars just took the air for the choke right from where this tube is. Ford found out that dirt would eventually plug the air off and the choke wouldn't work correctly. I also have a 74 and I do not have the fresh air tube on mine. I don't drive in the rain or on dusty roads so I'm not at all worried about it! If you drive your car in reasonably clean conditions, you will have no problem.
You can use either port, but do not plug the other one! All those two ports are is a cast in channel that goes through the manifold. It heats air and the tube that goes to the choke has a vacuum draw when the engine is running. This tube will get very hot so that is why it's covered with an asbestos wrap and connects to the choke with a flare fitting. Do not try to use any kind of hose on this! It will burn up! I like copper tubing because it bends easily and doesn't rust!
Just curious?? Why does the one tube get hot and the other does not? Is it because of the vacuum draw on the carb.
The one tube is inlet air ( cool ), the other is heated air ( very hot ). You'll notice that the inlet tube has the hose very far away from the manifold, so it won't burn!
I'm bring this post forward as it was useful in answering my recent post on heat tubes. Thanks to Steve and Crazy Comet. MD
