Actual curb weight is 3607 lbs for a '79 Z28.
'70 Chevelle SS454 curb weight is 3836 lbs.
'70 Dart Swinger 340 is 3170 lbs
'70 Road Runner 383 is 3646 lbs
Clearly the Dart is far lighter, giving it a better power to weight ratio, coincidentally the same as a 1970 Nova SS at 3170 lbs.
All figures were result of google searches.