Yes it is compiled and bulky, it is a redhat default kernel which includes the support for Pentium family processors, networking, ide, etc., but doesn't contain the support for ntfs, for instance. If you are updating kernel-source as well then there are different configuration fies dropped into /usr/src/linux-2.4/configs directory you should copy the configuration file for your architecture to ../.config
cp /usr/src/linux-2.4/configs/kernel-version-release-architecture.config /usr/src/linux-2.4/.config
and then recompile your kernel, you can choose what already is in .config or you can costumize it, etc
make dep clean bzImage modules modules_install
after successfull recompile you should update your initrd.img file with
/sbin/mkinitrd /boot/initrd-kernel.version-release.img Kernel.Version-Release
copy the compressed kernel image to /boot and adjust LILO/GRUB as needed.
P.S. I've had some disastrous consequences upgrading kernels by rpm's, so I stick with http://www.kernel.org