Early 327 engines in nascar
The early NASCAR 327 Chevy engine, famously optimized by Smokey Yunick, was a lightweight, high-revving small-block that punched above its weight against bigger engines by exploiting rule loopholes for a nimble, efficient competitor, leveraging its oversquare design (4.00" bore x 3.25" stroke) and high-RPM breathing for surprising performance, making it a legend in the muscle car and racing scene despite GM's initial focus on larger blocks.
This video explains the design and performance of the 327 small-block engine:
