I spent more than $100 trying to restore the column shifter on my 82 C10. But almost none of the parts were available, and that was 5 years ago. I ended up making some bushings using shim stock to reduce the slop. Also used a hard plastic cap I found somewhere as a bushing! The slop was pretty much gone, but a part I couldn't find was the "shift bowl" which is the cast "pot metal" part that the shift handle connects to. Mine had been cracked where the handle attaches and repaired with epoxy, but I simply didn't trust it. Can't weld those things, either. Sold the whole thing to a guy with a sloppy column, but he had an NOS shift bowl. Perfect for him!
Here's shift bowl:
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On another note, some of the slop can be caused by worn shift forks, which are still available and can be easily replaced.
Also, keep in mind the Saginaws came with up to 4 different sets of gear ratios depending on year and engine size. The base 6-cylinder engines got a trans with a 3.50 1st gear for lots of torque multiplication to get rolling. At the other extreme was trans with 2.54 first gear for large V-8s. And one or two more in the middle for 292 six and 305. 2nd gear ratios were also different to keep the RPM drops between gears optimal.
If a trans with 3.50 1st gear was used behind a V-8, it probably wouldn't handle the torque multiplication for very long.
Same was true for Muncie 4-speeds -- most engines got a 2.52 (or 2.56) 1st gear, whereas the high performance engines got 2.20, and above that was 2.20 with straighter cut gears for even more torque handing capability.