Simplify the following text for a Grade 7 native English-speaking person.
Original: The series was staged as the Formula 3000 European Championship in 1985 , as the Formula 3000 Intercontinental Championship in 1986 and 1987 and then as the Formula 3000 International Championship from 1988 to 2004 .
Simplified: Formula 3000 was a type of formula racing , below Formula One and above Formula Three . It was named because the cars were powered by 3000 cc engines .