you have a couple of viable options:
1) fiberglass monoleafs and cal-tracs(or similar device), however, you'd still be limited with tire size, could mini-tub it though and gain some room
2) keep the leaf springs, add spring sliders, throw in some ladder bars and minitubs
3) ditch the leaf springs, go with ladder bar/coil over, and minitubs or full tubs
4) go four link/coil over/full tub
For a 10 second car that could be driven to shows and cruise-ins, I would go with #3, that way the chassis will be as streetable as the motor, plus it be strong and hook well. Ladder bar setups are fairly easy to install and setup, plus they won't bind when going over bumps like a 4 link will. On the Chris Alston site,
www.cachassisworks.com, there should be a how-to link where they put ladder bars on a 67 chevelle, maybe it will answer some questions for you.