Never heard of a 428 FT. FT usually stands for Ford Truck, and was used for the truck-only 360, as well as larger displacement engines in heavy trucks. In Cobras, only FE series engines were used in the big block cars. Some had 427s, and others had 428 PI (police interceptors) due to supply problems with the racier 427. They appear nearly identical under the hoods of Cobra, with the same intake, exhaust, and valve covers.