This report describes the nature of two fundamental innovations in computer applications necessary to diffuse computer usage completely into the general design and development process-list processing and parametric representation of curves and surfaces. Acquisition of current change level information regarding engine design parameters looms as a major part of the total activity. List processing techniques are required for an operationally feasible procedure for data base maintenance. Parametric representation of curves and surfaces must be incorporated so that engine assembly and detail drawings can be “stored” in computer memory. The payoff lies in establishment of one nonredundant data base serving all activities related to the valve train. Such an integrated design engineering aid can be easily applied to other engine subsystems and ultimately the total engine.