Tip of the day, Hood spring installation
This is the very simplest spring installation I know of. The description is for a hood spring but I have used it MANY times on all kinds of springs including trunk torsion bars. Below is a drawing that may make it clearer. I would go out there and take a picture but it is raining like a cow peeing through a pole bridge.
Have a friend hold the hood open all the way, or if you have to, use a prop. Hook the spring onto the rear of the hinge and keep tension on it so it doesn’t fall off. With the other hand hook your chain hook onto the spring hook and pull, keeping that tension. Now, I usually wrap the chain around my hand like you do when you are the anchor man in a tug-o-war. All the while maintaining the tension so the spring doesn’t fall off the hinge at the back. Pull on the chain stretching the spring out so you can hook the spring end onto the hinge hook. It may seem like you can’t get the chain hook off the spring, but it comes off rather easy if you start to remove it before the spring is set all the way down in the bottom of the hook on the hinge.
This method leaves you in complete control, YOU are in control of the spring and it will not fly off, I have NEVER had it fly off in any way while using this method.
It is best to mount the hinges to the car, but if you had to you could do the same thing with the hinge mounted in a vice. I have always used a chain that has a hook made out of 1/8” mild steel. But I have seen many guys use a link that opens and just hook it over the end of the chain. You could also make a dandy tool by cutting a link off making a hook. Then MIG weld it to the last link on the chain.