There's maybe 3 or 4 in the entire league. None of which 340+ lbs.
If you actually watch Walker play his tape this past year was just downright awful. He was consistently dominated off the LOS in a way no 340lb player should be.
You could place him at edge but that would require him to drop a significant amount of weight and he just doesn't have any actual pass rush moves nor the motor to play it well IMO.
Guys like Calais always had a motor. Walkers motor is very sub par. He often givens half effort on plays. Just too many red flags.