* Displacement: The most obvious difference is the cubic inch displacement. A 454 is, as the name implies, 454 cubic inches. A 496 is 496 cubic inches. This extra displacement means a larger combustion chamber and potential for significantly more power.
* Bore and Stroke: To achieve the larger displacement, the 496 typically has a larger bore (diameter of the cylinder) and/or a longer stroke (the distance the piston travels). These changes necessitate internal modifications.
* Power Output: The 496 will generally produce significantly more horsepower and torque than a 454, all else being equal (same heads, intake, etc.). The exact difference depends on the specific engine builds and modifications.
* Internal Components: While sharing a basic big-block Chevy architecture, the 496 may require different internal components like crankshafts, pistons, connecting rods, and possibly even cylinder blocks due to the increased stress from the larger displacement.
* Weight: The 496 will likely be slightly heavier due to its larger size and potentially heavier internal components.
* Applications: Both engines were used in various applications, but the 496 was often chosen for high-performance applications where maximum power was desired, such as racing or heavy-duty towing.
In summary, a 496 is a larger, more powerful version of a 454 big-block Chevy engine, requiring different internal components and producing substantially more power. The differences extend to the size and weight of all internal parts. If you are actually referring to a 354ci engine, it's not a standard GM big-block engine and would require further clarification.
