Replace the old, cracked, or damaged exhaust manifold on your 2006-2007 Chevy/GMC 6.6L LLY/LBZ Duramax and get your engine running right. Durable, high-silicon ductile iron manifolds are offered as an upgrade or stock replacement for many applications. Exhaust manifolds can fail due to cracks or leaks from heat cycles, age, and other extreme conditions. These leaks can reduce power, and also hurt engine efficiency. BD-Power, Dorman, AFE, ATS, and many more are just some of the manufacturers you can find.