Before any body work can begin, there is a list of some important things that must be done. This is the ideal way to do it. The closer the vehicle is to assembled as if it’s finished, the better.
The smallest of things, like one bolt not quite tight enough, can throw everything off in the end.
♦️Make sure the weight of the vehicle is fully on its suspension. At minimum, have jack stands under the suspension, as close to the wheels as possible. The best is to have the vehicle sitting on its wheels.
♦️Is the vehicle level? This is even more important if the coils are replaced with ‘mock up’ piece of square stock.
♦️Make sure all the proper body mounts are in place.
♦️Torque all body mounts evenly.
♦️Make sure the proper core support mounts are in place and torqued evenly.
♦️Have all (new) weather strip installed. It can make panels fit very differently. It can be taped in place rather than glued.
♦️Are there rubber bumpers or adjusters used for any of the panels? Make sure they are in and adjusted
♦️Make sure all hinges are bolted down tightly, and have all the fasteners in them.
♦️Have the engine and transmission in. The weight makes a difference with how everything flexes. It’s possible the doors might fit differently without the weight there.
♦️Weight in the doors to simulate the windows and regulators.
♦️Interior weight. Sometimes, especially on convertibles, the weight of the interior can affect the fitment of door gaps. Add some simulated weight inside the car.
♦️Gas Tank. Add some weight to simulate a full gas tank.
♦️Inner fenders and engine bay panels should be installed and tightened down, as they can affect how the fenders fit.
♦️♦️In reality, not all of this can or will always be done. But the more thorough you are, the better everything will fit in the end, and the fewer surprises there will be.