Sammy used the pedal distortion into clean amps for all of Acid Bath but went to using it as a boost when he joined Crowbar with Kirk. Acid Bath is more brutal than a bag of 50 slam bands.
(If I try to become a harsh vocalist, Sammy's backup vocals to Dax will be my main influence. Glass-melting rancor.)
Also None so Vile is the pedal slaved into a JCM800
Metalzone as a boost is killer. I remember hearing Cannibal Corpse used it to boost their Rectifiers back in the day, so we tried it in my bandmate's Valve King. Turned it into a firebreather. And you have the parametric EQ as a bonus.