A specialized indexing conveyor oven, Model DTI-1244 allows customers to streamline the preheating process by eliminating steps that required additional handling of the products. The thermoforming oven uses both electricity and gas to preheat products and includes a two-tier system that performs both preheating functions simultaneously. The upper tier has a contact press that utilizes two heated platens with a decline conveyor. The upper and lower platens are heated by electric rod elements. The lower tier has a natural gas heated convection oven and a wire mesh conveyor belt. Product is loaded simultaneously on the entrance end of both the upper and lower tiers and is indexed one position into the contact press and the convection oven chamber. Once preheated, both products index one more position, exiting the oven simultaneously. As used by a Tier 1 automotive supplier that manufactures interior components, the parts heated by the systems are then matched together to form a preheated vehicle seat ready to be press formed into a single unit.