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).
Comparative table of engine specifications for various British, Continental, and American cars.
| Identifier | ExFiles\Box 128\1\ scan0004 | |
| Date | 19th April 1922 guessed | |
| British Cars. Make and model. No.of cyls. Bore and stroke. Piston displacement Cu.ins. % larger than Goshawk 11 Goshawk. 6 3 X 4½ 190.8 30 HP. Armstrong- 6 3½ X 5¼ 303.1 + 58.2% Siddeley. 20 HP. Austin. 4 3¾ X 5 220.9 + 15.0% 16 HP. Bentley. 4 3⅛ X 5⅛ 180.2 - 5.5% 20 HP. Crossley. 4 3⅜ X 5⅛ 226.1 + 18.4% 30 HP. Crossley. 4 4 X 5½ 276.5 + 45.3% 20 HP. Daimler. 4 3⅛ X 5⅛ 197.2 + 3.6% 20 HP. Ruston Hornsby. 4 3¾ X 5⅛ 226.4 + 19.4% 25 HP. Stroker Squire. 6 3⅛ X 5⅛ 235.9 + 23.6% 16 HP. Sunbeam. 4 3⅛ X 5⅛ 180.2 - 5.5% 24 HP. Sunbeam. 6 3⅛ X 5⅛ 270.4 + 42.1% 36 HP. Talbot. 6 3⅛ X 5⅛ 235.9 + 23.6% 25 HP. Vauxhall. 4 3⅜ X 5⅛ 243.0 + 27.8% 30 HP. Vauxhall. 4 3½ X 5½ 277.1 + 45.7% 20 HP. Wolseley. 6 3⅛ X 5⅛ 235.9 + 23.6% Continental Cars. 16 HP½ Delage. 4 3.15 X 5.91 184 - 3.1% 25 HP. Delage. 6 3.15 X 5.91 276 + 45.3% 20 HP. Delaunay- 6 3.07 X 5.51 245 + 28.8% Belleville. 16 HP. Lorraine- 6 2.95 X 5.12 209 + 10.0% Dietrich. 18 HP. Voisin. 4 3.74 X 5.51 242 + 27.3% 20 HP. Minerva. 4 3.5 X 5.5 217 + 14.2% 20 HP. Fiat. 6 2.95 X 5.12 210 + 10.5% American Cars. Buick (six) 6 3⅜ X 4½ 241.6 + 26.8% Essex. 4 3⅜ X 5 178.9 - 6.7% Ford. 4 3¾ X 4 176.7 - 6.7% Hudson (super-six) 6 3½ X 5 288.6 + 51.1% Packard (single-six) 6 3⅜ X 4½ 241.6 + 26.8% Studebaker(light-six) 6 3⅛ X 4½ 207.1 + 8.1% | ||