to me that sounds more psych/prog.
so I'd recommend Pink Floyd to you, they have a lot of compositions lasting around 20 minutes, and are mainly instrumental throughout.
You may like that, not sure.
I don't really know what your tastes are and what you're after, so a bit more detail would be better.
I'd also recommend using last.fm to find artists similair to those you like.
http://www.last.fm/Music/Funkadelic