Wheelie bars. We also have a steel cable on the driver side running from the front to the rear to try and reduce body roll.
We also have metal braces bolted to the heads and frame to try and keep the motor from twisting (again, trying to minimize body roll).
There's only so much you can do with a Vega and their 96 inch wheelbase though. I think we've got the 4-link and rear shocks adjusted pretty close now. It doesn't twist very much at all and it just does bring the left front off the ground. Of course, I dont have near the motor that it has had, but even with the 406, it didnt twist too bad (by twist I mean bring the left front way higher then the right front).