what is the weight difference between the 5th gen elkys w/ a 305 and their malibu counterparts?

These are curb weights for the 1979 base models with a V6 engine:

Malibu 2 door Coupe - 3076 lb
Malibu 4 door Sedan - 3081 lb
Malibu 4 door Wagon - 3249 lb
El Camino - 3178 lb

thanks a lot :)