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 specifications for 12-cylinder engines from various car manufacturers.
| Identifier | ExFiles\Box 179\2\ img200 | |
| Date | 1st February 1932 | |
| 12 CYLINDER ENGINES. 1.2.32. Car. Capacity. 7000 Balance Wts. Damper. Journal Dia. No of Spring Packard 8131 470 Yes Yes 2.75" 4 Auburn 450 Yes Yes 4 Lincoln 7350 350 Yes Yes 2.50 7 Pierce Arrow F.D. 470 Yes No 2.68 7 Cadillac 6036 450 Yes 7 Voisin 4886 480 Yes A.{Mr Adams}(V?) 3 Hispano 9100 600 Tatra 6031 630 Yes 3.375 8 Maybach 6970 600 Yes Yes 3.350 8 Horch 6100 600 Yes Yes 1 Daimler 6511 600 Yes Yes 7 Proposed R.R. 6230 290 | ||