H-D made the Ironhead Sportster all the way to 1985. Of course they're known for hanging on to old tech as long as possible. I wouldn't mind owning one myself, or a nice Shovelhead. But then there are a bunch of motorcycles I'd love to have lol.
B&S started doing aluminum engines around the early 1960s from what I'm seeing on Wikipedia. My family has had a few lawnmowers with flathead Briggs engines over the years and they were aluminum.