I hate to pore crap on u'alls fine mess but all 64-72 A body rear ends are not the same. The mounting for the springs are different and I believe that is 67 or 68 they changed the angle of the upper control arms. I also believe that the housing lenghts are slightly different. I found out from some one on the forum that the rear end width on a 442 is narrower than a GTO of the same year{66}. Go figure. Hot Rod or Car Craft did a article on rearends of the 10 and 12 bolts but I don't remember when. Possible maybe to find on their web site? No an A body is the medium size Cutlass/442 Skylark/GS Tempest/Lemans
/GTO and Chevelles. Spend the money and call one of the Rear end sellers in the magazine like Randy's
www.ringpinion.com or gears and rears at reiderracing.com or Curry's in street rodders mag or maybe contact old pinion head on the forum here. I don't know what exactly he does but I believe he is a restorer and he does sell parts and is very knowledgeable. Sorry if I got this wrong old pinion head. To me a 9" is the way to go but a Dana 44 will take a licking and go on ticking to. 9" are easier to swap gear ratios. If u'all rebuild the rear end have it professionaly done as it takes special expensive tools to do it right. Good luck
DRIVE IT LIKE U'ALL STOLE IT!
connman