aFe Power Twisted Steel Exhaust Headers are designed using optimum tube lengths and mitered collectors for maximum flow and velocity for power delivery across the entire power band. Large 1/2" thick head flanges and stainless steel tubing deliver a strong and powerful exhaust upgrade. Smooth curves and increased diameter of this header helps remove restriction and keeps exhaust gas flowing smoothly for improved performance and durability. Twisted Steel Headers are 100% bolt-on with no modifications necessary.