[sfm6s]

I have a question about the output shaft on a '63 aluminium (L1/L7) T10 with K gears. What is the ridged section, below the splines, that forms a stop for the yoke? I can't see it shown on any of the exploded diagrams. Also what colour speedo gear for a period SW guage , 3.54 diff and 275/55/15 tyres; any ideas?