The cubic inch equals 16.387 cubic centimetres. Used in US automotive engineering for engine displacement (e.g., "350 cubic inch V8 = 5.7 L") and in firearms (bullet cartridges). Most of the rest of the world uses cc or litres.
Real-world: 350 cu in V8 = 5.7 L engine. 302 cu in Ford V8 = 4.9 L. Modern specs typically give litres.
Read full cubic inch reference →The UK imperial gallon equals 4.54609 litres exactly. Defined in 1824 as the volume of 10 pounds of water at 62 °F. Still used for fuel economy reporting in the UK and some older industrial contexts. The UK imperial gallon is about 20% larger than the US gallon.
Real-world: UK petrol sold by litre since 1995, but economy is quoted in UK mpg: a diesel car at 60 mpg (UK) uses 4.7 L/100 km.
Read full uk gallon reference →