below is an excerpt from the LFS book.
Currently, you can't build an LFS system by using linux-2.6.x instead of linux-2.4.x. This is because the kernel headers from 2.6.x are incompatible with other programs in LFS-5.x and will lead to compile errors. It is recommended to use linux-2.4.x in your build until LFS releases a new version which includes the 2.6.x kernel; according to the roadmap this will be LFS-6.0.
my question if 2.6 headers cause problems with the LFS build, why don't my 2.6 headers cause problems when I build programs on my gentoo system.
I am basing my assumption that the kernel headers are in my kernel source, is that correct?