I know of a guy who used a 69 chevy Malibu (spelling?) frame that was a direct fit for an AD truck. It actually looked really good! I am not sure all the dimensions for your 45, but it might be worth a look. It allowed for upgraded steering, handling, etc. The only issue that might come up was the bend in the frame by the axle. I am asking my buddy to send pictures that I will post on the website.
Chris
