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).
Modifications to the Phantom III 4 Port Head to accommodate different types of rockers and tappets.
| Identifier | ExFiles\Box 93\4\ scan0105 | |
| Date | 10th February 1937 | |
| HPS{Horace Percy Smith - Experimental Factory Mgr} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} 319 Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}10/M.10.2.37. Phantom III 4 Port Head. We have asked By to incorporate bossing on the 4 port head (E88758) that will suit either hydraulic tappets (std) or the solid rockers. Will you please see that this modification is included on heads now being made for us to (E88758) The above means that the 4 port head can go into production with the existing standard hydraulic tappets and when experiments are complete the solid rockers can be used without any alteration, other than the drilling of the rocker pedestal stud in a different position. We have instructed that the D.O. let you have details of the modifications as soon as possible. Our requirements on this common head will be 2 sets for hydraulic and 2 sets for solid rockers. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||