Quoted from Don Roth’s Article: “Noah’s Flood and God’s Calendar”:
The chronological facts that are recorded in the account in the book of Genesis clearly establish a period of 385 days in the year of the Noachian Flood. This year length is significant because it is the exact number of days required for an excessive leap year in the Hebrew Calendar. This remarkable account of the Flood, which God inspired to be recorded in his Work, is the indisputable evidence that the Hebrew Calendar bears His stamp of approval. There can be no doubt that the calculations of the Hebrew Calendar have been the basis of God’s true calendar from the beginning.