No and no.
The only rear end upgrades that will bolt in to your 64 are from other A-bodies. You can either stay with the small 7 1/4" rear or go to an 8 1/4" rear from a 72 and up A-body or and 8 3/4" from a 72-earlier A-body if you are looking for a bolt-in. Either way you will have to have the driveshaft shortened.
Also the 8 3/4 rear end is the one with the smooth round back to the housing and the drop-out center section, very similar to a Ford 9".