The NEW Livernois BOSS Series cylinder heads are built for customers who are looking for products that offer a no compromise approach. We start with factory CNC'd BOSS Mustang cylinder head castings and add a Livernois custom valve job to increase flow. We also upgrade the intake valves to aftermarket stainless steel again to increase flow. We use the factory Boss exhaust valves as they are already very good. We also add our Powerstorm valve springs for higher rpm potential. These components and services used in these products are selected based off of years of development and the latest in racing technology. Each and every product in the Boss cylinder heads has been developed and tested in a rigorous R&D process to produce only the highest quality most durable products on the market. Each part is designed and tested to work together as a system to maximize power and durability. Every aspect of the design, testing and final product machining and assembly are handled in house. This allows for complete control of the entire process start to finish. If interested please PM us or give me a call at 313-561-5500 extension 104 my name is Cody and i will be glad to assist you!