Don't waste your time with the early forged rods. They didn't get squat for heat treating, so they are very soft, thus the nickname "rubber rods". They are no better than later cast rods, which really aren't bad parts at all. People over-revving their engines or not replacing the rod bolts with high strength units at rebuild time are why the factory cast rods have a bad rep. For a street engine, a set of factory rods, resized with ARP bolts is plenty good enough to 5500 RPM in a 455 or 6000 RPM in a 400. If you want to upgrade for peace of mind, there are now plenty of very affordable aftermarket offerings out there that would still be cheaper than properly setting up a set of the old forged rods (having them heat treated then completely rebuilt/resized).
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'72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car!
'73 Firebird 400/4-speed Black on Black, mix & match.