IMHO if you want the vocal to sound distorted in that metally way I recommend a combination of the following:
1.) Forget a distortion pedal--this always makes the vocal sound small to me. Unless you add the slightest (like under 5%) of distortion with a lot of clean boost going on.
2.) Let the singer "cup" the mic and just wail on it like they do live. They are more comfortable this way and the cupping allows the mic to get really close to the singer--increasing the amount of diaphragm distortion going on which is, IMHO, an essential ingredient to that type of sound.
3.) Run an analog mixer in the red. This will add some distortion to it! In general the more higher end the mixer the better it will sound clipping.
4.) NEVER clip the recorded output if the recorder is digital. Leave a good 6 db of headroom or more like you would with all signals.
5.) However, if you have a good reel to reel analog recorder feel free to let it clip into the red! This will probably give you the best 'distorted vocal' tone of all. This is a major argument for the continued use of analog machines--tape saturation. Generally, if you record in the red you probably don't want the mixer to be in the red. However, if you really want some major overdrive run both into the red like they used to do it.
6.) Somewhat borrowed from industrial bands is the idea of 'compressor distortion' such as Al Jourgenson from Ministry. Run a number of compressors in a row set to squash the crap out of the signal--it will end up making it sound pretty distorted, yet still maintain clarity, which is why I prefer to use compressors for distortion over any distortion pedal/device/plugin. Instant Ministry voice if you run enough of them. I've red that Jourgenson uses six sequential compressors to achieve his distorted tone.
7.) Distortion plugins sound wretched to me for vocals. If you want something to sound distorted RECORD it distorted. That's my policy.
In essence, my argument is that you can use a combination of microphone, mixer, compressor and analog recorder distortion to yield a distorted sound.