Just like the fully built up engines, Aluminator Short Blocks are hand assembled and use Manley connecting rods with ARP rod bolts and Mahle(R) forged pistons. Two versions are available ? 9.5: and 11.0:1 compression ratio. These Aluminator Short Blocks serve as a strong foundation for the enthusiast that wants to spec and finish a Coyote build to his or her particular application and needs. Ford Performance Engineers have taken care of the toughest part of building a new engine by designing a strong and durable Short Block that offers a wide range of power possibilities. And every Ford Performance Aluminator Short Block is precision internal balanced and hand assembled in the U.S. with performance clearances. Ford Performance offers a number of components to finish the build including the simple to install Controls Pack M-6017-504V to get it up and running in just about any vehicle ? from Early Model Mustangs to resto-rods to classic muscle cars to street rods. WARNING: This part is designed and intended for competition use only. It should not be installed on a vehicle that is driven on public roads and highways. Installation of this art on a vehicle driven on public roads and highways is likely to violate U.S. and Canadian laws and regulations relating to motor vehicle emissions.