GM has lots of plants in Mexico and many of the parts are made down there. If you own a GM car or SUV check you door sticker where the VIN is located it will tell you if it was made in Mexico.
If you happen to own a Ford power stroke and think it is American made guess again, most of the body parts are from Canada, the starter is from Japan, the vacum pump is from Hungary, the brake rotors and drums could be from China or Brazil, and other small parts are from all over.
GM uses American standard nuts and bolts on the engine but everything else is metric and Ford is right behind them.
There is no such thing as a American built car these days!