You've got a bunch of options, depending on what your needs are.

If you're looking for something strong, try a new Currie crate rear end... they feature the 9+ center, any gear you want, strong axles, a variety of differential choices, and several rear brake options.     Currie Site

They make 'em for the '64 - '67 GM A bodies that bolt right in. 

The sway bar on these cars bolts to the lower control arms.. there are several good ones out there.   We used a Hotchkis bar on our '65 and there were no fitment issues at all.    You just want to have either boxed original style control arms or aftermarket arms... the sway bar won't work well with stock, c-shaped un-boxed arms.    But you don't want those, anyway!