A big, heavy, bad-handling car made in Detroit. A road locomotive.
This expression was common in the 1960s when cars that handled well were made in Europe. American cars were oversized, wallowing pigs, and you had to make reservations to go around a corner.
Someone who is addicted to obtaining money and building wealth. A money addict and fanatic. Breadheads often work more than one full-time job, and some even participate in illicit activities to "obtain the bread".