Is there any difference repo wise between 64bit and 32 bit

[Frank Murphy (Frankly3d)]

How would I.

Lets say on the one install Fedora 11,
use a 64bit kernel for a 64bit cpu.
With everything else being 32bit i586

I would probably have to include
in fedora.repo and updates.repo
excludepkgs=kernel\*

What is needed to include the 64bit kernel,
and have it updated automatically to same

Frank