Sounds like the frame is maybe bent into a "diamond" shape. Or one front horn is bent up from the Dukes of Hazzard jumping. If the bumpers appear to sit level, check the frame for the diamond condition by measuring diagonally to common points. May have to get it on a hoist to do this. Can also do it on the garage floor by using a plumb bob to drop points that you can mark on the floor and measure to. Try and check 4 points as far apart as possible, diagonal measurements should be within 1/8" of each other, 1/4" max. Does the car dog track at all if you follow it down the road? Does it chew up one tire faster than the rest?
