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 of performance and specification data for Vauxhall I4 and Rover I6 models.
| Identifier | ExFiles\Box 128\3\ scan0062 | |
| Date | 10th February 1939 | |
| Vauxhall I4 and Rover I6. Litres Weight Unladen Cwts. Axle Ratio Revs per Mile Litres per Ton Litres per Mile Litres per Ton Mile Secs. 20to40 MPH. Accel. Ft/Sec.2 Vauxhall I4.2door 1935 'Motor' 12-2-35. | 1.781 | 22.5 | 4.77 | 3695 | 1.58 | 6580 | 5780 | 10 | 2.93 Vauxhall I4.4door 1939. Autocar 10-2-39 | 1.781 | 22.35 | 4.71 | 3651 | 1.59 | 6510 | 5820 | 12.5 | 2.35 Rover I6 1939 Autocar 15-7-38 | 2.147 | 28.76 | 4.7 | 3420 | 1.49 | 7340 | 5105 | 14.2 | 2.06 | ||