I was thinking about it some more.

1) Is it just 8!? For the first row, there are 8 choices. For the second row, there are 7 choices, etc...

2) Is it just 8^8? Every row has to be hit, but now it doesn't matter if a row is repeated. First row has 8 choices, second row has 8 choices, etc...

I feel like these answers are too easy. Am I missing something?