This already happens but 20% of the timeAnother idea would be a 0 Atk Guzzlord.
I would support having only Earthquake added to its movepool from this tbf. Heavy Slam would be better than Iron Head and Iron Tail due to consistency. Drain Punch is rather weak and Guzzlord gigantic HP stat makes it not recover much. This and Hammer Arm doesn't really provide much coverage with the moves it already has. Dragon Claw is too weak and Body Slam is unreliable.Physical moves: Dragon Claw, Body Slam, Hammer Arm, Earthquake, Stone Edge, Iron Head, Iron Tail, Knock Off, Crunch, Poison Jab, Drain Punch
As mentioned before all special attacks do happen already. Dragon Pulse I don't think is worth it and Snarl is not very good in singles. Flamethrower over Fire Blast would be odd.Special Moves: Draco Meteor, Dark Pulse, Sludge Bomb, Fire Blast, Dragon Pulse, Snarl, Flamethrower
Overall, Physical only Guzzlord is kinda off the table but what I can take from this is to add Earthquake to compliment its Attack Boosts more.