Being a Cummins guy, I don't think I could think of anything cooler than the aluminum block Cummins that the folks at Scheid Diesel came up with.

 The block, even with sleeves, sheds 140lb of weight, making it perfect for race vehicles that need a little less weight, like the Scheid Diesel dragster. It also can hold upwards of 2,500 horsepower (they haven't found the limit yet) which makes it perfect for banzai-class sled pullers as well. We'll take two please!