Summary:In a global market place, speed is a new competitive weapon. An ability to accelerate development can have far-reaching impact on product success. Unfortunately, there is a lack of adequate plastic design know-how for metal to plastic conversion programs. Most designers still tend to think in terms of direct part-for-part replacement. As a result, development of these parts require several cycles of “make it and break it” which adds both cost and time to the overall development cycle time. To optimize development cycle, a thorough understanding of structural behavior of a part under specified load and temperature is very critical. The lack of proper design methodologies has been recognized by the plastic industry and appropriate measures are underway through joint efforts of auto manufacturers, resin suppliers, software developers and governments. Until adequate design methodology is developed, it is highly desirable to disseminate experience, knowledge and technology.This paper compares high performance engineering polymers available today for under-hood applications. It includes an example of an end cap showing value-added capabilities such as design for machining and assembly (DFMA), team approach and computer aided engineering being used for a most cost-effective custom molding solution. These techniques should be part of standard design procedure for conversion programs to cope with the challenges of today and tomorrow.