Not sure of the slugs you are talking about. What are they?
SWS sells a cross shaft for the chevell. But its meant to be used with metal bushings.
http://www.southwestspeed.com/?sec=view_part&id=14391
Here are the arms they use with those shafts, screw in ball joints but for mustang spindles.
http://www.southwestspeed.com/?sec=v...0Racing%20Arms
Here is there stock arms.
http://www.southwestspeed.com/?sec=view_part&id=28398