I have an 11 horse riding lawn mower engine. Looking for projects I
can do with it. I have thought that it would be handy to have a
generator around this winter to power the blower to my furnace incase
the power goes out. Any ideas on where to get a cheap generator head?

Have you already seen the site http://www.otherpower.com/ ?
Somewhere on the site is a project for building a battery charger from
an old gas engine. Also a lot of other interesting stuff!
Enjoy!
Reto