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).
Comparison drawing of a 6 Cylinder 3.5 Bore Sleeve Valve engine and a Big Bore Bentley engine.
| Identifier | ExFiles\Box 133\2\ scan0161 | |
| Date | 2nd July 1935 guessed | |
| BENTLEY 26.5 SLEEVE VALVE 29.0 FIG. 2 6 CYL. 3.5 BORE S/V ENGINE COMPARED WITH BIG BORE BENTLEY. | ||