Find a flat, level floor and use plumb bobs from places that should be the same dimensions, side to side, and also length. Those grease fittings on the control arm pivots would be a good place to start. Then find somewhere such as the rear spring pivots, etc. to establish rear reference points that should be in the same position side to side. Also make diagonal measurements to check for "parallelogram" warp of the frame. I put masking tape on the floor and use a felt tip pen to get an exact position of the plumb bob point.
Jerry
