[Maxiboy]

Paolo,

I'm not technical when it comes to engines, but hopefully I can still enlighten/explain the conversion for you.

1 cubic inch = 16.387cc (from 2.54 * 2.54 * 2.54, as 1 inch = 2.54 centimetres).

Therefore 302 cubic inches is 302 * 16.387 (= 4948.874cc, i.e. 5 litres)

427 cubic inches is 6997.249cc (i.e. 7 litres)

Hope this is what you were after.

Cheers,

Max