Simplify the following text for a Grade 5 native English-speaking person.
Original: The final evolution of the Cosworth-Kent , in 1965 , was the MAE , when new rules were introduced in Formula 3 allowing 1000 c engines .
Simplified: The final version of the Cosworth-Kent , in 1965 , was the MAE . It was used in Formula 3 when 1000 c engines were allowed .