Currently, the only manufacturer of aftermarket oil pumps for the big block Chrysler is Melling Engine Parts. Melling has been in business since 1947, for over 6 decades. They currently manufacture over 3 million oil pumps every year. For most all applications, we recommend the high volume unit, M63HV. Aside from the billet and aluminum racing pumps made by Milodon, Keith Black and others, Melling is THE only source for stock replacement type cast iron pumps. Don't forget the attaching bolts for your new pump also.