[computerworks]

(...and remember, not much is cast in stone with originals!)

Front turn signals MUST produce amber light on all cars of model year 1963 and newer in the US and Canada. Manufacturers at that time stayed with their existing tooling and used amber bulbs to comply.

As I see it, all 289 Cobras came with clear lenses. As a carry-over, all 427 Comp cars and most of the early S/C's (delivered up to mid-to-late 1966) also were supplied with clear lenses. Street cars, shipped as 1966 model-year (CSX3100 and up), had amber lenses.

Both the clear and the amber were twist-off lenses.

(They say that...) When AC saw the supply of Hillman rectangular taillights drying up, they switched over to the dual-round taillights...somewhere around CSX3200. At the same time, they switched the front amber lens to the same type lens as the taillight: held on by screws instead of twist-on.