First, if you have an Auto Zone near you, see them. They sell Holley rebuilds for Carter applications. I got one for my 250. They may be help you with the choke tube issue. As a next resort, check with your local Ford dealer. Their service department should have access to old technical bulletins which they should have on microfiche which may address that situation. As a last resort, call Ford customer service in Michigan. They are very helpful and courteous. Their number is 1-800-392-3673. They should be able to find the info you need. You can always check with a local mechanic who has experience with older Fords. Personally, unfortunately, I cannot be of help to you. I have little experience with 200's as I have a 250. I am going to do some reference for you in the meantime and hopefully someone else here may know the fix. Good luck.