A 4.0" exhaust cutout refers to a component used in automotive exhaust systems. The "4.0" specification refers to the diameter of the exhaust cutout's opening. In this case, it's a 4.0-inch diameter opening. This size measurement is critical because it needs to match the diameter of the exhaust piping to which it will be installed.
Nice kit, with out the premium price. A must for power strokes. Comes from over seas. Took about 10 days to receive, with good Communication along the way. Going to consider other offerings from SPELAB.
Good material, good prices,
Only the flanges need to adapt, perfect fit just need modifications in the connection to the pipes, different angle 📐 flange need more than 90 degrees to fit the pipes , other than that is perfect fit in the engine M54, my chassis is E46 thanks for the product