The differences can include:
* Displacement: While both might be *called* a "350," the exact displacement might vary slightly.
* Internal components: Truck engines are typically built more robustly to handle heavier loads and towing. This means stronger internals like connecting rods, pistons, and crankshaft.
* Block casting: The actual engine block itself will often be a different casting designed for the increased stress.
* Accessories: The mounting points for accessories like alternators and power steering pumps may differ.
* Exhaust manifolds/headers: These are usually different due to the differences in engine bay layout.
You cannot simply swap a truck 350 into a car without significant modifications (and likely modifications to the car's chassis as well).