The Malibu has it's own frame and it's the same for Coupe and Sedan. The G-body Wagon has different rear rails and body mounts. The El Camino has a longer wheelbase. The Monte Carlo, Regal, Cutlass, Grand Prix & Grand Am have longer front frame horns because of the longer nose and are known as a "G Plus" frame. People DO put G Plus frames under Malibus. They collapse the front bumper shocks to make it work.
Tommy
Tommy