If anyone is referencing the lightest shipping weight available for a V* upgrade, they also have to consider that when you start replacing the original /6, small rear and other light duty stuff with a V8 and related components, the weight goes back up.
The Dart Lite and Feather Dusters always facinated me, even if they don't end up the lightest when upgraded with V8 stuff. It's been a while, but the hoods are about 10-15 lbs lighter and the trunks about 5-8 lbs. HUGE difference between the bumpers that have the aluminum reinforcement bracket and the steel version. But those only bolt to the shock absorber bumper brackets. The standard bumpers with regular bumper brackets are probably lighter than a Lite/Feather bumper combo.
I've heard of some racers even "uncrimp" the aluminum bracing and recrimp it under an earlier A-body hood ('70-'72) to save weight!