Build BIG Modular Power. The Ford Performance 5.3L Modular Stroker short block is a great way to build modular power - from mild to wild - naturally aspirated or supercharged - 2 valve - 3 valve or 4 valve. Ford Performance Engineers have taken care of the toughest part of building a new engine by designing a strong and durable shortblock that offers a wide range of power possibilities. Ford Performance uses only the best parts, starting with the BOSS Modular block, and adding forged Eagle steel crankshaft, forged Eagle H-beam connecting rods with floating piston pins, and forged Mahle pistons. Bored and stroked to 5.3 liters, this short block is precision internal balanced and ready to be finished to your specific application. 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.