Preheat the oven to 425 degrees F.
Wash and dry the potatoes, but don't bother to peel them, and cut them into about 3/4-inch dice. Toss in a large oven tray and pour over the oil, smulching around with your hands to mix well. Separate the head of garlic into cloves adding them to the tray, and roast for about 1 hour, turning once or twice during that time, until crispy and golden but still soft on the inside. When they're done, remove to a large plate and sprinkle with salt.