The clod is cut from the shoulder, which is considered to be a part of the chuck. While a chuck roll is the extension of the same muscle that the ribeye comes from, along with all of the connecting neck muscles and layers, the clod is the muscles of the upper arm- namely the bicep and tricep group.
We have had good success with separating these arm muscle groups into individual cuts and they cook up quite tender when done low and slow. When bundled all together, there can be interconnective tissue that canbe undesirable, and each piece may or may not cook at the same
Remember, bovine use their front legs for motion, so the muscles are generaly more dense and can be tougher than the hind legs. (The farther from the hooves and the horns, the more tender- as a general rule.).
Personally, when I process a front quarter, I make sure to trim, roll and tie the tricep (what I call a Bolar). and same with a bicep (Fish Roast). Excellent Dutch Oven fodder.
