How do you get the 7000 years from Noah to the End?

Mr. Campings case for the basis of his timeline:
2 Peter chapter 3:8
"But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day."

Then...

Genesis 7:4
"For yet seven days, and I will cause it to rain upon the earth forty days and forty nights; and every living substance that I have made will I destroy from off the face of the earth"

So.. going against the rule that scripture must compare with scripture Mr. Camping built his entire story off of these two pieces of scripture. He states that the words god spoke to Noah about 7 days can be converted into 7 x 1000 OR 7000 years because in 2 Peter 3:8 God said that a day is like a thousand years.

Wait! What is that I see in Genisis 7:4, something about 40 days? Are you thinking what Im thinking? God made it rain for 40 thousand years? How can Mr. Camping take a part of a scripture and apply his thousand years to what helps him most but not to another item that would blow it away? Because he is a false prophet that manipulates the word of god. God told Noah to get into the arc in seven days because he was going to die drowned like the rest of them if he did not. God didnt want Noah to die like that, he just wanted to clense the Earth and repopulate it with Noahs seed.