Perhaps these two diagrams may be of some help in your drive shaft section alignment.

The 1st pic is from a 1966 Chevrolet Truck Illustration and Special Information Catalog, showing the common 2 and 2-1/2 ton propeller shaft layout. You should be able to zoom in to see the orientation of the yokes from transmission output to rear axle, section by section.

The 2nd pic is another diagram from a 1968 Chevy C10-60 Shop manual showing the propeller shaft sections and yoke orientations. I checked and it's actual the same diagram going back to a 1963 Shop Manual, so should apply to your '66.

Maybe enough to help you get the segments all back together and lined up as they should be?

Let us know how it turns out.
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~ Dan
1951 Chevy 3 window 3100
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"My Grandpa Carl's Truck and How it Became Mine"
1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver)
US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)