This is the installation of a '98 Camaro LS1/T56 in an '81 Malibu. The '78 - '87 Malibu, Monte Carlo, El Camino, Regal and Cutlass should be similar.
The front sheet metal was removed for ease of access(PIC). The front crossmember was notched and boxed to clear the oil pan(PIC). The trans tunnel was raised and widened to fit the T56(PIC). The Camaro engine mounts that bolt to the LS1 block were retained in their stock location. The Malibu engine mount shells that originally bolted to the engine were mounted on the frame and the Camaro mounts sit down in them with the long bolt running through them. The stock Camaro manifolds and cats were used with the left Oxygen Sensor moved to clear the frame. Clutch master cylinder and reservoir(PIC). New reservoir mount that raised it higher(PIC). Aftermarket fuel pressure regulator(PIC). Fuse/relay box above the computer(PIC). Computer was mounted then the wiring was rerouted around the engine and the wires lengthened to reach the computer. '95 Camaro dual fan unit was used on the stock radiator(PIC). The Camaro shroud was turned upside down and bolted to a trimmed down Malibu shroud. The LS1 P/S lines were used with some careful rebending of both lines and shortening the return line. The inlet duct was created from a 3 1/2" exhaust elbow.(PIC)
Street and Performance has headers available for this swap and they were working on producing custom engine mounts.