Start by checking the simple things. Body mounts and if your frame might be rotted around them. Most g-bodies have some rot around the bushings. Replace the mounts and fix the frame with the repair washers then go from there. You can help a lot with the simple things, factory frame braces from Grand Prix's, aftermarket rear frame/bumper tie in, radiator cross bars, back seats cross bars, etc. I'm guessing your a drag guy so the next thing is rear control arms and then a rear ant-roll bar-not a sway bar. TRZ a site sponsor makes them and have heard nothing but good things about them. check here http://www.trzmotorsports.com/319.html#rear