69 Charger Spindles

This is what I learned when I had my 69 Charger. The 73-76 A body disc brake spindle and the 62-71 B Body and 70-74 E Body drum brake spindles are the same dimensionally. So since the 63-72 A body drum brake spindle is the same dimensionally as the 73-76 disc spindle, it was reasonable to assume one could put the 62-71 B Body drum spindle on the 63-76 A Body. But why, since discs work so much better than drums. So my Charger got the 73-76 A Body discs which stopped so much better than the drums. This is just my opinion and what was published concerning drums vs discs - it might have been Ehrenburg who did the research.