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).
Status list of chassis numbers for a flywheel ring gear modification.
| Identifier | ExFiles\Box 10\5\ 05-page110 | |
| Date | 14th October 1938 guessed | |
| No. T.D. 129 FLYWHEEL RING GEAR Chassis Nos. on which the above modification is complete: - P.E.F. - G.S.F. - R.E.F. Chassis Nos. on which the modification is NOT complete: - F.E.F. - G.E.F. - S.E.F. - E.O.F. - M.D.W. | ||