Hey, I just saw your message and I might be able to help. The 84 and 85 suspensions are the narrowest of the C4 Corvette suspensions. As I recall the front suspension is right at 59" wide. I have not narrowed a front end, but it would be simple to do. You will need a custom steering rack though to keep the geometry correct. Those can be quite expensive. The 2004 front suspensions are very wide and much more money. The 84 to 96 Corvette front suspensions are very good and quite inexpensive.
I have narrowed the C4 rear suspensions with good results. You can only take about an inch off each side without doing major surgery. The rear suspension geometry isn't that great, but it sure isn't that bad.