* Exhaust Manifolds/Headers: The 454 is slightly larger, meaning the existing exhaust manifolds or headers designed for the 427 likely won't fit. Custom headers or modifications will be necessary.
* Oil Pan: The oil pan might need to be modified or replaced to clear the frame and suspension components. A different sump style might be required.
* Engine Mounts: While the mounts might be *close*, adjustments or custom mounts are often needed to ensure proper alignment and secure the larger engine.
* Power Steering and Other Accessories: The placement and routing of power steering, alternator, and other accessories might need adjustments due to the slightly larger size of the 454.
* Transmission: While a 427 typically used a heavy-duty transmission, ensuring compatibility with the 454's higher torque output is crucial. The transmission's bellhousing might need modification or replacement.
In short, it's a *feasible* swap, but it's not a straightforward bolt-in job. A significant amount of fabrication and custom work is likely required to successfully install a 454 into a '66 Corvette that previously housed a 427. Experienced mechanics with expertise in classic car engine swaps are highly recommended.
