The Napier Railton of John Cobb had two Napier Lion broad arrow engines, these were, depending on whose archive you believe, either donated by, or brought from Betty Carstairs, and had, at one time, powered her 'Estelle' powerboats.
Now according to hand written notes of Reid Railton, the only mod's needed, or done to these engines for the records were, pre war, the fitting of an anti-stall device, and post war, the changing of the cork floats in the carb's and some jetting issues.
So, reading documents that have come into my hands I get the following,
Flying mile record,1939, John Cobb, Napier Railton, capacity 48,029 cc (makes sense for two 24 litre Lions!!). But for 1947 the capacity is officially listed as 47,886cc. It's only a small reduction, but so small as to rule out sleeving down the engines, and why would you anyway, you'd more likely bore them out!
Just curious as to how this has occurred, but they are pretty official documents!
Edited by f1steveuk, 15 September 2012 - 14:44.