* Engine Mounts: The 396's larger size and different mounting points will require new motor mounts or significant modification of the existing ones. You'll likely need mounts specifically designed for a big-block in a '71 Malibu.
* Transmission: The 396 likely came with a different transmission (e.g., a TH400) than the 350 (possibly a TH350 or Powerglide). You'll need the appropriate transmission and associated bellhousing to mate to the 396. This might involve a driveshaft change as well.
* Exhaust: The 396's exhaust manifolds or headers will be different, requiring new exhaust components.
* Steering: The larger engine might interfere with steering components, potentially requiring modifications or different components.
* Cooling System: The 396 will generate more heat and may need a larger radiator and potentially a different fan setup.
* Wiring Harness: You might need to modify the existing wiring harness or use a harness designed for a big-block.
* Brakes: Consider upgrading the brakes to handle the increased power of the 396.
* Body Modifications: Depending on the specific 396 and the exact fitment, you might need to do some minor bodywork to accommodate the larger engine.
* K-Member: The K-member (front suspension crossmember) may need to be swapped out, or modified to fit the big-block engine.
In short, while feasible, this swap is a major project requiring mechanical expertise, specialized tools, and likely a significant budget. It's not something a beginner should undertake. You'll need to research specific parts compatibility and consult with experienced muscle car mechanics.
