Due to the small volumes of British Salmson cars produced, the manufacturing was organized in such a way that the cars were made in batches of 24 or 25 cars each. There are no factory records presently available to the B.S.O.C. Archivist, so the estimated numbers of cars produced is based on an analysis of chassis numbers.
The S4C chassis batches were numbered AZ101-AZ124, BZ201-BZ224, CZ301-CZ324 etc. The highest chassis number found is from the JZ10xx-series, which would give a maximum of 10 batches with a maximum of 25 cars in each. Most of the batches had 24 cars and it is not clear if the 10th batch was complete. This way of calculating would result in approximately 230 cars; definitely not more than 250 S4C cars produced. This includes the S4C 12/70 model that originates from the standard batches, but had some details shifted to fit customer demands for this slightly higher performance model. The high performance 12/70 cars have an extra S embedded in the chassis number. Example: DZS408.
There were only 2 batches made for the S4D. The chassis numbers typically found are in the range AD101-AD124 and BD201-BD224. This would give a maximum of 48-50 S4D chassis made.
Very few 6-cylinder cars were made, even less than one batch. The present estimate of S6D chassis produced is in the range of 12-15 cars. The cars were given chassis numbers A6ZS101-A6ZS112.
By adding the estimated number of cars a minimum total of 290 cars and a maximum of 315 could be assumed. Let´s assume that 300 cars were made between 1934 and 1939 which makes about 60 cars per year.