From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
List of modifications including a free exhaust and a larger carburetter.
| Identifier | ExFiles\Box 29\3\ Scan020 | |
| Date | 6th October 1911 guessed | |
| 3. Free exhaust, and 4. Larger carburetter. T.N. | ||