I replaced the one in my 68 with one from Summit Racing.. OER brand I believe? It was about 70 bucks and it came with the new plug so ya don’t have to reuse the original one.
I have the same one in my Duster and Barracuda. I'm not sure if I installed the lever wrong or what but the lever in both cars has a ton of play in it. Up and down as well as back and forth. Is yours the same way?