By Carlos de Paula Around 1968, the horsepower difference between 3 liter Formula 1 and 1.6 liter Formula 2 cars was great. There was a place for an intermediate, high horsepower single seater category in Europe, powered by stock blocks. The U.S. Formula A was just such a formula: stock block 5.0 liter single seater cars, theoretically fast and inexpensive to run, that were being ran in the USA since 1967 The formula was thus adopted in Europe for a 1969 championship. Read more about it here https://www.amazon.com/dp/1732674426 S