Well I've been looking alot into turning my auto el camino into a 5 speed. Basically it's a difficult process, alot of costume things. And usually anywhere $4,000+ to get it right.
Take a look at this website, they make 5speeds for Novas also... will give you somewhat of an idea. Their kits are 4 to 5 speed and auto to 5speed conversion, but it will give you the same idea I think.

Classic Chevy 5 Speed