Are you trying to come up with a spirited driver or a purposed-built canyon carver? Spirited Drives is simple bolt-ons such as larger springs, heavy roll bars, 2-way adjustable shocks, rear end suspension parts, etc.
A purposed-built road course project would start with a proper chassis and tin it with your '65's sheet metal.
Truck frames twist which is ok if you are hauling stuff, however sucks if you want to go fast and change directions.
