jt,

After a search through GMpartswiki this linked page indicates there were two different Overall Length (O.L.) steering shafts:

SHAFT ASSY, steering gear, with worm for 63-66 Series 10-30 trucks.

Have added a pic below with those items marked for easy viewing.

As indicated, the two shafts appear to be different due to the length. You will need to measure your existing unit and compare to what the seller is trying to offer to see if they are the same.

Hope this is helpful???

Dan
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Screenshot 2023-01-20 at 18-12-53 GMPartsWiki - Chassis and Body Parts Catalog P&A 72TL May 1979.png (186.73 KB, 74 downloads)
1963-66 Series 10-30 Steering column info

~ Dan
1951 Chevy 3 window 3100
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