I'll throw in an unpaid advertisement for the Spohn Performance parts. I run many of them, and George Baxter used many of them on his 8.60-second (1.30 60-ft) 30th SS convertible. Steve Spohn's own car is a 3rd Gen, so he knows them as well as anybody.
Components to consider include:
-tubular LCA's
-LCA relocation brackets (major traction improvement on my car)
-tubular panhard rod
-adjustable torque arm
-springs and shocks selected based on how you use the car
I'm sure there are some other 3rd Gen specific items for the front end, and I'll leave those to someone else.