Pderouss/Cal: Thanks. Rinsey Mills and the Registry are other sources that documents SC's as being fitted with dual quads.
Remember the first 53 chasis were built as comp cars. After failure to homologate for FIA it was then the remaining cars that were not sold as comp cars were fitted out to SC specs (street/competition)
Ron: I don't think there are any records that detailed that will tell us what cars had singles and what cars had duals.
The information in recognized treatises and books such as Rinsey Mills and the Registry is a good source. Good enough for me anyway.