The Cosworth Process is well recognized for its ability to produce high quality, dimensionally accurate aluminum castings. The process was designed from first principles with casting quality as the main focus. Ford transformed this process into a high volume production system in the early 1990's at its Windsor Aluminum Plant and this plant continues to manufacture world-class aluminum cylinder block castings today as Nemak Canada. The one drawback (if any) of the original process is the resultant microstructure due to the relatively slow solidification rate in heavy sections in the sand mould. The secondary dendrite arm spacing combined with typical automotive grade alloys limits the mechanical properties in certain areas of the casting. The innovation discussed in this paper is an augmentation of the original Cosworth Process to include an integral chill that increases local solidification rates and drives casting performance to new levels.