The aluminum heads were never standard equipment or optional equipment on Cobras. The Cobras (w/5.0L) came with cast iron GT40 heads, different than the GT40 X, Y or Z heads from Ford Racing. The X and Y heads have the passages for air injection and egr; whether or not they have a qualifying CARB number I don't know. The Z head is newer (last couple of years) -- don't know if it's set up to receive the smog equipment or if it has a CARB number either. FRPP can tell you -- that's who I'd call.