Baseball originates from bat-and-ball games of medieval Britain. For centuries an assortment of variants were played in Britain and France under many different names. By the mid 18th century baseball emerged in Britain, while a game called "rounders" was played in France. Rounders was the first ball-and-bat game to be introduced to those colonies that would eventually become the USA, near the end of the 18th century. Shortly thereafter baseball was introduced into Canada. Canada would introduce baseball to its southern neighbors not long after that.
Baseball is not American at all.
Also commonly called a "Frankfurter", the hotdog originated in medieval Frankfurt, Germany. They were popularized in America in the latter half of the 19th century when a German immigrant began selling them in Coney Island.
Hotdogs are not American at all.
When the new land was colonized the new inhabitants found that there were no native apple trees, except for the crabapple which was not very suitable for cooking due to its berry sized acidic/sour fruit. European seeds had to be imported and cultivated for many years before the colonies had access to apples. The colonies were instead partial to meat based pies, inspired by the famous Cornwall pasty. When domestically grown apples finally became available in the colonies they were used in the cider industry. In the 18th century Swedish, Dutch, and British influences introduced the idea of an apple based dessert pasty, which eventually became known as "apple pie."
Apple pie is not American at all.
You finally get close on this one. But even though Chevrolet was founded in the US, you may notice that the name is not exactly English. The company was founded by a Swiss immigrant (after whom it was named) who arrived in NYC as an adult after first living in France and then Quebec. Accordingly, you only get half credit here.
So based on what you've said, you're 1/8th American.