The Boss 5.0 block is a 4.6L deck height, 94mm cylinder bore cast iron block. The block uses a proprietary iron mix to yield the strongest possible casting strength with the least porosity and greatest consistency. NOTE The Boss 5.0L modular block does not have a finish milled head deck surface and the cylinder bores are rough honed. 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.