Are the frames on a 1978 Malibu and Trans Am interchangeable?

No, the frames on a 1978 Chevrolet Malibu and a 1978 Pontiac Trans Am are not interchangeable. They are different cars with different chassis designs and dimensions. While both are GM products from the same era, the Malibu is a full-size car and the Trans Am is a pony car built on a different platform (F-body). Their frame designs are fundamentally incompatible.