Motorsports governing body introduced new sports car rules for 1968; Group 6 Prototypes with a maximum of 3 litres. In effect the CSI were making obsolete the ‘unlimited cars’ the 7 litre ‘pushrod’ Ford MkIV being built by Ford and the 4 litre ‘racing engine’ Ferrari P4Ferrari, which they considered too fast for the race tracks of the time.
Ferrari, in time honored fashion didn’t race in 1968 in protest at this sudden rule change but returned in 1969 with the Group 6 312P
https://primotipo.com/2014/09/21/enzo-ferrari-framed-by-his-312p-ferrari-312p-1969/
