Today's low-octane unleaded gas mandates a compression ratio reduction for '60s supercars. The easiest way to lower compression is usually to swap on late-model heads; not only do their larger ...

You might have heard about high compression ratios, but what exactly are they, and what kind of effect do they have on an engine's fuel efficiency?

Low- And High-Compression Fuel Economy Engines: The Techniques Are About The Same, But The Approach To Each Is Somewhat Different. A.Most stock cylinder heads have factory-cut undercuts of the type ...