The Ford Racing 5.4L improved cylinder block is a heavy duty, cast iron block that delivers every ounce of performance you have come to expect from Ford Racing. Being an improved production replacement block, this block is cast with a newer design and casting methods to deliver low-end improvements, minimizing noise, vibration, and harshness from your engine. It is the perfect compliment to your newly built 5.4L engine, or the perfect replacement for a broken down or worn out block.Precision machined to exacting standards, this cylinder block is ready to assemble right out of the box!.