GTO's are full-framed cars except for 74's (stub-chassis type). The only correct replacement comes from a 70 Pontiac A-Body (LeMans or GTO) however, any 68 to 72 GM A-Body (Skylark, Chevelle, Cutlass) 2-door frame could be made to work. Changing a frame is a big job. A repair might be easier, if the car is so rough that the frame is wasted then the rest of it must be awful.(posted 8689 days ago)