AD = Advance Design [no 'd'], a GM advertising name for the 47-54 ... Art Deco for the 41-46 isn't a GM term, but is commonly used as 'deco' or the whole term, not the initials
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics
