2 x 512S chassis were used in the development of Modulo. They were the last 2 unsold of the 25 built for homologation according to Paolo Martin, Modulo's designer at Pininfarina. The second one was used for a 1:1 scale mock up. The 0864 number was allocated to a spare 612 Can Am engine only, NOT to a chassis or anything to do with Modulo as far as I can gather. I found it interesting that in my correspondence with him he always referred to the car as the "Module" rather than Modulo.