- Custom Rotational Molding Specialists Since 1979 At Inca Molded Products we have been a leader in the rotational molding industry since 1979. We are located in Nashville, TN and have a 60, 000 square foot manufacturing facility. Inca developed the first permanently installed plastic fuel tank in the marine industry, helping us become one of the leading suppliers in the trade. In 1992, Custom ...www.incaproducts.com