Here you will find CentOS compatible RPMs and SRPMs for the GNU Linux-Libre kernel.
There are two different versions available: an RPM build from the vanilla kernel sources provdied by the FSFLA, and a custom deblobbed RPM build from the kernel sources provided by CentOS (dubbed DeCentOS by Alexandre Oliva for Deblobbed CentOS).
To install, download the RPMs and run ‘rpm -ivh kernel-package.rpm’. This will install the kernel (and headers and source if you install those packages as well). Then create your initial ramdisk (e.g. mkinitrd /boot/initrd-3.10.0-gnu.img 3.10.0-gnu). Then finally all you have to do is update your bootloader (e.g. grub2-mkconfig -o /boot/grub2/grub.cfg)
Last but not least, under the CentOS compatible builds you will find a .repo file for you to place in /etc/yum.repos.d/ (or wherever you keep your yum repo files).