Woodcock says not only are they big, but they've got great technique.
"You've got to have both. They are strong men and they've got technique to come with it."
He says they're relatively familiar with the South Americans.
"Played them a few times, and obviously there's plenty of video footage and stuff like that so you get a fair idea of what they're going to bring and it's no secret they're going to bring some pretty powerful forwards."
The Pumas will name their side in Wellington this evening with a couple of changes expected from the side which drew with South Africa.
Juan Martin Hernandez is expected to return at first five.