70 Dart bucket seat springs

Question my drivers bucket seat base is shot very bouncy. Is there a way to tighten it up or does the spring/frame need to be replaced. Has anyone purchased a frame or springs what’s available new or do I look for a good used one.

Before you spend any money, zip tie the springs together in a bunch of different places to connect them all so they share the load better. The more zip ties, the better. I improved the firmness on my seat a ton by doing this.