From listening to his vocals on Cattle Decapitation (if I have the wrong guy please let me know) it looks like he gives off very little air unlike, just for example reasons, Mark Jansen from Epica.
Could you please give an example as to what you mean with growls, everyone seems to have their own definition and this would help to help you.
I'd say if you can get the Jaymee Vendera extreme vocals CD, you should as it is very detailed and will at least steer you in the right direction without damaging your vocals.
A majority of vocal power comes from your diaphragm so learning to breathe from your stomach rather than your chest will help you a lot.