So missing are the June ACO verifications techniques documents by the french. My theory; the swap of chassisnumbers + engines is: ACO demands before a certain date to publish the drivers and racenumbers. Ferraris Parkes and Scarfiotti (works drivers) tested a lot of times with 0856. They did the Le Mans test with 0856 (April) with no. 21. If someone from CSAI or Ferrari made a mistake with the entry documents by listing Parkes and Scarfiotti as no. 21 for 0858 that might be the reason to do a swap; drivers raced with a car they know very well: 0856. (Daytona, Monza, LM Test and Spa) Swap the tag and engine with 0858 so the works drivers were able to race with “their” 0856. As Ferrari has a lot of records for 0858 they have for 0856 as well. In their documents lays the answer. What other logical reason can be the reason Ferari Classiche stating 0858 is the “24” at Le Mans?