So later 273s did come with cast cranks. Interesting. I've never seen one. I will say this though, about the lighter 273 and early 318 rods. Evidently, Mopar Performance didn't think they were much weaker because they offered a performance version of them with ARP rod bolts and those rods are pretty sought after today. I've said it before. I've never seen a broken factory rod, early light one or later. Let me clarify that. I've never seen a rod "just let go". I've seen some that were broken, but something else always caused it. Broken rod bolt, broken crankshaft, or "something" that had fallen into the crankcase, but never just a rod itself "just break" with no outside influence. Never. Not one.