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).
Specification document for the standardisation of a 4 port head, detailing alterations.
| Identifier | ExFiles\Box 171\2\ img312 | |
| Date | 2nd March 1937 | |
| SPECIFICATION FOR STANDARDISATION OF 4 PORT HEAD. To detailed instructions By/CS.1/EH.2.3.37. with the following alternations. E.88447 exhaust valves (strengthened) E.88782 Inlet valves (solid) Water pipe modification to Lec.5710. | ||