67-69 camaro subframe is the only one that will truly fit. The 70-81 will work but you will have tire/fender clearance issues unless you install it at normal ride height. The G-body subframe will work well but is labor/fab intensive as the steering box causes a major interference with the core support resulting in front sheet metal alignment issues and modified radiator mounting.
My $0.02 - use a IFS kit.
