F1 race length over the years.

1950-1953 300km minimum or 3 hours whichever came first.

1954-1957 500km or 3 hours whichever came first.

1958-1965 300km to 500km or 2 hours whichever came first.

1966-1970 300km to 400km or 2 hours whichever came first.

1971-1972 200mi (321.87km) now the maximum distance.

1973-1976 200mi (321.87km) or 2 hours whichever was shorter.

1977-1980 250km minimum 200mi (321.87km) or 2 hours the maximum.

1981-1983 250km minimum 320km or 2 hours the maximum.

1984–1987 Warmup Lap part of race distance. 300km minimum 320km or 2 hours maximum.

1988 Warmup Lap not part of race distance. 300km minimum 320km or 2 hours maximum.

1989-2011 305km or 2 hours whichever comes first.

2012-Present 305km or 2 hours whichever comes first. Maximum of four hours with red flags added.

Races will still be longer than the "Golden age". You won't notice the change.