Quote: "I thought the shaft on a big-block is integral to the distributor cam gear? I thought you only went with the hardened (bronze gear?) if you had a roller cam? Or am I off?"

Yeah, you're a little off; Mopar Perf. makes an input shaft with a Forged(?) HARDENED End. With the heavier oil and volume of flow comes more of a chance you'll round off the tip, as we've all done with allen wrenches ...

The gear end stays the same.