That's nice and all, but Mopar never made a .8447 A-body torsion bar. brian is right on, I would guess the numbers you listed are the date codes.
This is the best guide I have for relating the ID #'s, part #'s and diameters. The rates listed in this one are calculated by the author of the chart though, and don't match the rates that Mopar actually published officially. The difference is probably that these were calculated with a generic constant for spring steel, while Mopar actually used the exact constant based on the metallurgy of the bars. Either that or the author of this chart used a slightly different length for the LCA which is totally possible if it was measured. Again Mopar would have had the exact number.
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This is a great list of the part #'s and rates, this is the Mopar published data for the rates. But of course it doesn't list the ID #'s on the bars themselves, and it's missing the .85" bar.
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Here's another list, this one shows a few of the bars with ID #'s, diameters, and some of the measurements, as well as the factory paint stripe color you can find on the OE bars.
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