The forging numbers are pretty accurate for things such as connecting rods, to determine the wide tang/narrow tang issues, but there are some rods I've found that can have either, even with the same forging number, I show an example of that in my book. And that is the same for the big wrist pin/small wrist pin rods as well. So that makes physically measuring the rods a necessity to confirm which style you have before you order parts. The Stovebolt went through similar changes also with its main bearings. Rods, cranks and heads can all be swapped over time, so the date becomes less crucial because if the interchange possibilities than can skew the parts required based solely on dates.
