The most successful new engine in American racing today is a 90-degree pushrod V-8.

As an all-new engine, the R07 shares nothing with the old small-block Chevy or with GM's current production V-8s. Let's start with the block. Its bore spacing is 4.500 inches, compared with 4.400 inches for the small-block and Gen III/Gen IV engines. That means the crank, cam, and other major components will not interchange. However, the greater bore spacing allows coolant jacketing between cylinders, while previous small-blocks required siamesed bores to obtain cylinder diameters much beyond 4.060 inches. Also, the R07's block is cast in compacted graphite iron (CGI). Viewed under high magnification, CGI has a structure resembling sea coral-which makes it much stronger than traditional iron casting alloys. Blocks sinter-cast in CGI can be up to 75 percent stronger and significantly lighter at the same time.