You could go with a Jeep grand cherokee gear box conversion.
You can put in a 93-98 GC box either rebuilt from a part store or from a salvage yard. You then need a new rag joint and some cheap fittings (which can be found here,
http://lee-powersteering.com/rebuild-misc.htm )
Can be pretty cheap if you do the salvage yard route or maybe $150 if you buy from part stores. All-in-all, it provides a much more firm steering feel which helps when you are at highway speeds
Check this post out, different site but a lot of info on it.
http://www.chevelles.com/forums/showthread.php?t=334534