Why Choose Us? Our commitment to delivering customer-friendly and top-notch services has positioned us at the forefront of the best used engine suppliers in the US. Featured Used Chevrolet Engine Chevrolet engines are an American icon and the embodiment of the American Dream. However, the constant repairs can be very expensive. Used Chevrolet engines are one economical way to extend your vehicle’s life. Optimal Auto Parts, is the leading supplier in the USA and Canada for quality low-mileage used Chevrolet engines with a warranty on all models and sizes.