The AOD is your best bet, unless you want to start messing around with electronic shift versions (there are controllers available for the AOD-E/4R70W, not sure about the A4LD). Some of these may have had lock-up torque converters, but you can just leave that unplugged if that's the case (they run off the ECM, which a '76 302 ain't got). You'll need one that has the correct bellhousing pattern, which is known as the "Late Windsor". More info in these 2 links. Cross-reference the models at the top of the 1st link with the engines in the 2nd link (right-hand column only), and if it has a 4 speed auto, it should be an AOD.