I also determined the length and style of "gasser" style frame rail I'll be making, chopped the frame, and knocked out the inner sleeves to allow my new frame rails to fit further inside the original rails for a stronger connection. I also cleaned metal on the inside for adequate plug welding.
To allow room fro mocking up my rear suspension, determining my axle width and ultimately the wheel base of the car I started by modifying my body dolly. I redid and relocated the main supports that holds the car onto the dolly itself with thicker material and added flanges to the chassis cannot slide side to side, this allowed the rear suspension to be installed; added a section in the rear to keep the car from tipping back, and a section in front to allow for making my frame rails. I added some threaded rod to help with support and fine tuning when it comes time to level the frame rails. these should be enough to keep the cantilever bars from moving and allow to add a preload for fine tuning leveling if needed. that's the idea anyhow.
I also mocked where the wheels will sit (front to back. not necessarily height) decided to move the front wheels forward 2" for that altered look (and to give some room for fender well headers) note the pics are weird because I took pics through a window.