['ol Pinion head]

Factory driveshaft lengths with factory installed PONTIAC 8.2 10 bolt rear:

'67 Pontiac A-body 4 speed........... 60.00" center to center on u-joints (3R's)
'67 GTO T-400...........................................59.3 75" center to center

'68-72 Pontiac 2 door A-body, most common driveshaft, 56.00" center to center
'68-72 Pontiac 2 door A-body T-400 & '71-72 with Muncie w big output shaft... 55.375"

All above were mfg with a 3R u-joint, IF one is about to upgrade to a built '71-72 8.5 A-Body rear, driveshaft will need to be .875 shorter.

Parts stock... am down to about 1/2 a barrel of nice straight rust free 60's-70's GM A ,GP, & F-body driveshafts, none are in the 56.25" - 56.5" length.
That is an oddball length, don't believe there is factory 3R end driveshaft in that range.

My suggestion with the install of any non stock application transmission or rear end is to install the entire drivetrain before installing the decided on transmission yoke.
With the vehicle up on 4 ramps or on a 4 post lift, properly insert the slip yoke & pull out the prescribed amt (usually 3/4"), then carefully measure center to center
between the u-joint area of the slip yoke & the pinion flange.
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