Not sure if the sweet and sour meatballs you're thinking of are the ones my family loves but this is how we make them. I make small meatballs with ground beef, egg, a little milk, breadcrumbs and a bit of minced onion. Or you can buy a bag of frozen pre-made meatballs. Mix a 10 oz. jar of grape jelly and a 12 oz. bottle of chili sauce in a pan and heat it until the jelly melts and the mixture is smooth. Pour that over the meatballs. They're a big hit with my family and friends.
I ate King Vitaman too; I think it came out in the early 70's. I think it was similar to Captain Crunch, but was marketed as being more nutritious than other cereals. Also Quisp and Quake; from what I recall they all tasted pretty much the same and had way more sugar than today's version. Some of the cereals even had sugar in the name, which would be un-PC now...Sugar Pops, Super Sugar Crisp, etc.