OK, after a winter of waiting, I finally got my smaller projects finished and the garage cleaned up to the point where I can start on the ole' girl again. The Camaro is gone but I kept the front clip (since I had completely rebuilt it).
Now, I'm reading several of the threads here to get a feel for the procedure to graft it to the '57's frame rails.
Here's the Rear End Mock up.. '73 XJ6 Jag Rear IRS with mounting hardware. (Sorry, iphone didn't do it justice. I'll get the Nikon and do better)