This place sells historic race decal kits and they have the Cobra Decal Kits here
http://www.racelinedigital.com/store...ort=20a&page=1
This is the only one that I see and its the 1964 289 FIA World Championship decal kit.
http://www.racelinedigital.com/store...oducts_id=1943
I didnt look through all these pages but heres all the stripe kits they offer since you are just wanting the stripe.
http://www.racelinedigital.com/store...dex&cPath=6_31