All Shelby GT-350 cars used a 289 High Performance engine rated at 271hp, not a 302 CID engine. At the Shelby facility in Southern California, the exhaust manifolds, intake manifold and carbuetor were a few of the items replaced. The engine was upgraded with a different manifold and carburetor for a new rating of 306hp. The 66 GT-350H with the automatic trannsmissions, retained the Ford intake manifold and carburetor. Most GT-350H cars retained the fold down seat.
You need to do a serious review of your information.