I did a similar thing with my SX4 (<-------- Avatar photo), except I made a tubular frame for the body. I actually turned the car upside-down in my garage (seats, suspension and drivetrain removed) and fabricated the frame on the underside of the body. It was a lot easier than welding upside-down. I since scrapped the thrashed Eagle body, and have the frame and diffs for use on another project (1984 Mercedes-Benz 300D sedan). I actually have the bottom section of an M B sedan that I am going to use as a template to fab the frame to the underside of the car. It is light enough for 2 people to lift. That way I don't need a lift to hold the body over the frame to fab the mounts. You could do something similar, in that you could find a wrecked or rusted out Eagle and cut off everything above the frame members and pan. You could set it on the donor frame to fab the mounts. Once it is done, just raise the body on a lift and roll the chassis underneath and bolt it on. Simple, right?