dead markley tube overdrive

No. An overdrive is NOT a distortion.

Overdrive is to give a tube amp extra sweetness by pushing a hot signal into your preamp stage of a tube head.

If you want a slightly distorted tone out of one, you can get it, and it's suitable for blues or jazz, but not metal.

If you're looking for a good metal distortion, try the Boss HM-2 MT-2 or a Korg Hyper Distortion... for death metal and such...

The DS-1 is also another good boss pedal, though not over the top like the MT-2 metal zone.