My advice for him is go ahead with the cal trac/mono leaf setup. I wouldn't suggest SS springs, because as long as you're spending money go with the better technology available today. The only alternative I would suggest is stock springs from a 340 car if he can get em cheap, or work out his modified /6 springs to be the equivalent to them.
His first order of business is get that pinion angle right and some longer shocks. SS springs won't help a damn bit if those 2 things are still wrong.