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 parts fitted to experimental cars 4.EX and 6.EX.
| Identifier | ExFiles\Box 67\2\ scan0030 | |
| Date | 1st July 1920 | |
| X.3504a EFC. from RHC.{R. H. Coverley - Production Engineer} RHC{R. H. Coverley - Production Engineer}8/LG1.7.20. X.3507a X.3923. X.3764. The following have been fitted to 4.EX Car - Luggage Carrier N.310. Petrol Tank with side filler X.3889. The following has been fitted to 6.EX Car - Mascot for Radiator X.3456. RHC.{R. H. Coverley - Production Engineer} | ||