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).
Listing the design changes required for fitting a 25/30 4-port cylinder head.
| Identifier | ExFiles\Box 103\4\ scan0189 | |
| Date | 30th December 1936 | |
| BY.{R.W. Bailey - Chief Engineer} [crossed out] 519 Sundry Piles [Handwritten] c. Rm.{William Robotham - Chief Engineer} HPS.{Horace Percy Smith - Experimental Factory Mgr} E/JNR.{Charles L. Jenner}1/HP.30.12.36. 25/30 - 4 Port Cylinder Head - LeC.5350. We send you herewith the following designs which cover all the changes necessary to the engine to apply the 4 port cylinder head. LeC.5428 - Induction Pipes and Wire Fittings. It should be noted that the carburetter is not handed although it has been brought over to the other side of the engine. LeC.5429 - Controls - Hot Spot, and Petrol Drain Pipes. LeC.5430 - Air Silencer. LeC.5431 - Choke Controls and Flexible Petrol Supply Pipe. E/JNR.{Charles L. Jenner} | ||