Not too difficult if you're reasonably handy.  The only thing that
might be a pain is removning the radiator shroud without breaking the
upper mounting tabs.  They get kinda brittle when they're old.  You
can do the pump without removing the shroud, but it's a pain.

If you do remove the shroud, you may need to disconnect the vacuum
lines that run across the top of it.  Make sure you mark 'em so you
know which hose goes where when you reassemble.