4 into 1 Base Collectors

To Specify Outlet Size: Find the outlet range as shown in the picture on the left for the specific sku. Then write a measurement on or between the range in 1/8" increments. Description Burns Stainless 4-1 Merge Collectors (Header Collectors) are custom engineered for each application using our proprietary X-Design parametric custom exhaust design computer program. Merge Collectors combine high flow and high velocity to increase and broaden an engine's torque curve all the way to the horsepower peak and beyond. Our products feature the highest quality fabrication and TIG-welding.  Each is completely hand finished inside for proper flow. For drag racing and similar applications where a tailpipe is not required, megaphones fitted with reverse cones are invariably the best option. They produce maximum horsepower and maintain the highest and smoothest torque curve. Megaphones also offer the highest potential power past the peak without compromising the lower end of the power band on well-developed engine combinations with optimally short-header tube lengths and a well-chosen collector outlet diameter. For applications which require tailpipes, a NASCAR-style transition (long or short) and ring is normally recommended. If you are unsure which style is best for you, please call to discuss your specific application.