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).
Specifications for inlet/exhaust passage lengths and spark plug gap.
| Identifier | ExFiles\Box 127\4\ scan0068 | |
| Date | 19th August 1937 guessed | |
| -2- Lenth of passages. Inlet 5.25". Exhaust 5.50" and 6.25". Plugs. AC.K.11 Gap .0381 .040". Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards} | ||