In 1967 FIA announced a rule change for 1968 that prototypes were limited to 3 litres and sports cars to 5 litres but only after 50 had been built (Ford GT40, Lola T70, Ferrari 275LM). Ferrari boycotted sports car racing in 1968 in protest, and with small feilds FIA changed the rule for sports cars to a production run of 25 cars for 1969, so Porsche developed and built 25 917s. Ferrari developed the 312 for 1969, but this was proved uncompetitve against 5 litre cars and wasn't built or raced extensively. So Ferrari developed the 512 for 1970 but it only ran for 1 season, since the 5 litre cars were ineligible in 1971. Ferrari then developed a flat 12 312P. The upshot is that from 1967 through 1971 Ferrari won only ONE sports car race, while Porsche dominated.
But WI, in April 1968 when the '25 car' rule was announced, Ferrari built 25 developed 330Ps? They could use the 4.2 litre Can Am engine, and being the dodgy lot they are, scam the FIA by modifying existing 330s and 412s to get the numbers up and save them the expense and trouble of actually building 25 cars. Such a car would be ready and well sorted by the start of 1969, so should be quite successful in that season when the competition is undeveloped 917s and well sorted but slower 908s and 5 litre GT40s. Would avioding the failures and mistakes of this era mean that Ferrari would stay in the sports car racing game instead of dropping out in the 70s?