Pacemaker 4499: These headers are designed more for low-to-mid range power gains, making them good for street driving and a balanced power curve. They have a 4-1 design, which tends to give a deeper sound, especially noticeable at lower RPMs.
Pacemaker 4480: The 4480 model is generally aimed at performance gains across a broader RPM range, with a slight focus on high-end power. It’s also a 4-1 design but usually with longer primary pipes than the 4499, which helps with high-RPM power. Sound-wise, they’re a bit louder and more aggressive than the 4499.
Pacemaker 4480KC: The “KC” stands for Keramic Coating, which adds heat protection to keep exhaust temperatures down. This coating can help slightly with power retention by reducing under-hood temperatures, which could mean minor performance gains over the standard 4480, especially in sustained high-performance situations. It also provides a longer-lasting finish, so the extra cost is partly due to the durability of the ceramic coating. Sound-wise, it should be similar to the regular 4480.