John Kunkel
Registered User
The first 3 inches of the axle shaft are too small for resplining so the axle has to be at least 3" longer than the desired final length.
In the case of the A body, the finished shaft length is 28" so the donor shaft has to be at least 31". Shorter shafts sometimes work if they don't have a step-down outboard if the splines but it's iffy.
Some candidates:
'71-'73 B body wagon= 31 21/64"
'70-'73 C body= 31 21/64" (and '69 wagon)
'70-'74 E body = 29 31/32"
'65-'71 D100= 31 1/8"
'72-'74 D100= 31 21/64