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).
List of modifications and parts, including deturbulated heads and strengthened exhaust valves, with their associated references.
| Identifier | ExFiles\Box 91\1\ scan0436 | |
| Date | 19th October 1936 | |
| -4- Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}12/KW.19.10.36. (22) Deturbulated 4-port heads - Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell}4/KW.14.10.36. (23) Strengthened exhaust valves in S/SLV for 4-port head - Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell}10/JH.9.10.36. (24) Parts for Ph.III general - Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell}12/JH.6.10.36. (25) No.15 for 38-EX - Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell}20/KW.14.10.36. Hs{Lord Ernest Hives - Chair}/Em. | ||