mobile

As far as I understand there are values in the kernel that need to be modified to allow overclocking. Most custom ROMs come with modified kernels that allow this. I have a stock 4.3 rom with custom recovery and root. Is there a way to use one of the kernels from those custom ROMs? And is a 4.4 kernel compatible with Android 4.3? Rebuilding a kernel from scratch is beyond my powers and I don't want to mess with this or go that deep :)
Thanks in advance for any reply.