Is the 5.7 L V8 engine a big block?

No, a 5.7L V8 engine is generally considered a small-block engine, not a big-block. The terms "small-block" and "big-block" refer to engine families and their overall design and size, not just displacement. While a 5.7L engine is relatively large, it falls within the size and design parameters of small-block architectures used by manufacturers like Chevrolet and others.