To get the right tone from the Pantera album "Cowboys From Hell," 
you don't have to buy a million dollar tube amp. Most of the Pantera
tone that makes Dimebag Darrell famous is in the tunings that he uses
on his guitars.

For the album, Dimebag tuned his guitar to standard E tuning on all 
songs but Primal Concrete Sledge(that's in dropped D). The secret to 
matching his sound is tuning to standard or dropped D but setting your
tuner's frequency to 437hz. That will insure that you get a lot of the
sound that makes Dimebag a great. You'll also notice the difference 
straight away because most guitarists use 440hz.

Other songs in different frequencies include:
I'm broken-C# 445hz
5 minutes alone-Dropped C# 445hz
Planet Caravan-Eb 445hz
A New Level-Dropped C# 445hz
Walk-Dropped C# 445hz

More than half of the songs on other albums are in 445hz tuning.