* Displacement: The most obvious difference is their displacement. The 305 cubic inch (5.0L) engine has a smaller displacement than the 327 cubic inch (5.4L) engine. This directly impacts power output potential.
* Bore and Stroke: The 327 achieves its larger displacement through a larger bore (diameter of the cylinders). The 305 uses a longer stroke (the distance the piston travels) to achieve its smaller displacement. This difference in bore and stroke impacts the engine's characteristics – the 327 tends to rev higher and make more power at higher RPMs.
* Power Output: Generally, the 327, with its larger displacement, produced significantly more horsepower and torque than the 305, especially in its original high-performance versions. However, specific power output varies greatly depending on the year of manufacture, engine modifications, and the application.
* Design and Features: While both are small-block Chevys, the 327 benefited from earlier technological advancements and was available in higher-performance variants than the 305, which was introduced much later (in the early 1970s) in a time of fuel economy concerns and emission regulations. This resulted in design differences in components like heads, camshafts, and intake manifolds that affected their performance characteristics.
* Intended Application: The 327 was initially designed as a high-performance engine, while the 305 was more often found in lower-performance passenger vehicles, where fuel economy was a priority.
In short: The 327 was a more powerful, higher-revving engine originally intended for performance applications, whereas the 305 was a smaller, more fuel-efficient engine designed for more general use. While both are small-block Chevys, they have distinct characteristics reflecting their different design goals and eras.
