* Engine Mounts: The 350 uses different engine mounts than the original engine in the '56 truck. New motor mounts will be required.
* Transmission: The transmission used with the 350 will likely be different than the original truck's transmission. This might require adapting the transmission, driveshaft, and possibly the rear end.
* Exhaust System: A new exhaust system will be needed.
* Wiring Harness: The 350 will need a compatible wiring harness.
* Radiator and Cooling System: The cooling system might need upgrading to handle the 350's potential heat output.
* Firewall and Body Clearance: Depending on the specific 350 and its accessories, you might need to modify the firewall or body to accommodate the engine.
In short: it's a popular swap, but it's not a simple "drop-in" job. Expect to invest time, money, and mechanical skill. Many aftermarket companies offer parts to facilitate this swap, making it more manageable for experienced mechanics.
