There is also a metal tag attached to transmission side cover with the number 3915085 embossed on it. What does this number reference?
Paul
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That tag is the "assembly number" for the transmission - it identifies the specific combination of main, side cover, and tailhousing castings, gearset type and ratios, input and output shafts, and output shaft speedo drive gear diameter and tooth count to suit a specific usage. Although most Muncies look the same externally, there were about a dozen different "assemblies" used, and that part number tag (and the broadcast code) identified which one they were.