My friend got his 69 BB 383 Dart down to 2600 LBS maybe even a little less,, IIRC,, & it was all steel still & glass windows.
BB Mopar engines are heavy.
He only had the outer skins of the hood, trunk lid,etc.
The bumper brackets were really light & he still had steel bumpers.
Lightweight mitsubishi small alternator.
Motorplates & all. really a light car In my book,& if you looked @ the car from the outside ,,it looked to be all there.
MBHD