Swapping Macbook logic board

I have a Black Macbook (mid 2007 I believe) with a gma 950 integrated graphics chip. I wanted to get a for-parts Macbook with an Nvidia 9400m graphics card and swap the logic board in. As far as I know, the 9400m cards come on the late 2008 models.

Would I be able to do this?

Doubtful. Even if the external form factor is the same Apple has been known to introduce minor yet significant internal rearrangements that make swapping impossible. And that's only if the firmware will work, which is also a long shot.