The flood and Noah's story

Genesis 6-9 is basically talking about the judgement and recreation God has made to human being in Noah's age. In the flood, God destroys everything excepts Noah and his family somehow shows God's grace and mercy. God judges but still rescues at the same time. He rescues the life of Noah and his family drops a hint that the rescuer-ruler will bring human back to the Garden of Eden some day in the further. 6:5 says like "that every imagination of the thoughts of his heart was only evil continually" which seems conflicts with 6:8 "but Noah found grace in the eyes of the LOAD". In fact, it reveals the grace of God and emphasis the importance of the belief-- only those people who believe in God will be rescued and reward permanent peaceful life ultimately. In this case, Noah somewhat behaves like a rescuer-ruler but still ends with a sinner. He deserves to die because he builds a vineyard, becomes drunk on the wine and lies naked, which all violates God's inclination. The flood and Noah's death once again convince people the absolute power of God and the importance of the belief. I just wonder to know is there any special meaning for all the accurate number in Genesis 6-9?