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).
Performance graph comparing different high lift rockers and carburettors.
| Identifier | ExFiles\Box 92\2\ scan0143 | |
| Date | 9th August 1931 guessed | |
| COMPARISON OF HIGH LIFT ROCKERS RM{William Robotham - Chief Engineer} P 20 SMALL VALVE HEAD 4.75 C/R INLET VALVE THROAT 1.680 114° CAMSHAFT E.82448 TIMING AS IN RM{William Robotham - Chief Engineer} P 19 --- VALVE LIFT .525 — VALVE LIFT .470 CLAUDEL CARB. R R TWIN CHOKE CARB 1.4 THROAT NO APPRECIABLE DIFFERENCE IN LOW SPEED M.E.P WITH VALVE LIFT. B.H.P. R.P.M. B.M.E.P. LBS/SQ.IN INDUCTION DEPN. INS. HG. | ||