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).
Two graphs comparing the BMEP of 1937/1938 Buick and Oldsmobile engines.
| Identifier | ExFiles\Box 134\2\ scan0117 | |
| Date | 1st January 1937 guessed | |
| ① COMPARISON OF IMPROVEMENT BETWEEN 1937 AND 1938 BUICKS PUSH ROD B.M.E.P. CORRECTED TO N.T.P. ② COMPARISON BETWEEN TYPICAL SIDE VALVE AND PUSH ROD G.{Mr Griffiths - Chief Accountant / Mr Gnapp} M.{Mr Moon / Mr Moore} ENGINES. B.M.E.P. ENGINE | BORE | STROKE | DISP | H.P. / CU. INS. BUICK 5.55 | 3 3/32 | 4 1/8 | 248 OLDS 6.1 | 3 7/16 | 4 1/8 | 229 CORRECTED TO N.T.P. 1937 SERIES 40 BUICK O.H.V. 1937 OLDS SIDE VALVE | ||