first what’s the difference between "A"&"K" coded cars, i believe its just the engine ie hipo or just 289? i ask because i recently came into possession of a 66 GT Convertible and i believe its K coded but the engine has all the hipo parts. other then that the car is all original. how detrimental to my cars worth if it in fact has A code parts on a K coded car? i also want to do minor performance fixes like stiffer suspension/sway bars and billet wheels or some thing, but i dont want to do any thing that cant bee undone to make the car 100% original again, any suggestions?