Hellwig 68-72 GM A-Body Frame FX KitOne of the most effective ways to improve the stiffness and handling of GM A G Body is to box the factory chassis. This process could take considerable time with measuring, cutting and fitting steel panels, however Hellwig Products is making the task easy and even more effective with its custom fit Frame FX kit. This Part Fits: Year Make Model Submodel 1970,1972 Buick Skylark 350 1968 1972 Buick Skylark Base 1968 1972 Buick Skylark Custom 1968