The two 1967 Shelbys that I have owned did not have any kind of smog system. They have a flapper valve on the passenger side at the end of the exhaust manifold for warm up. You have a heat riser tube from the exhaust to the carburetor for the choke. I would look at some pictures of some orignal cars to find out what all you neeed. I have some pictures of my 1967 Shelby GT-500 on our website. Thanks, Keith
