Note: This is NOT a factory replacement. Factory turbos are a different flange size. This is for use with T4 Turbochargers ONLY which are all aftermarket.This 3-Piece 24 valve T4 Manifold is cast from Ductile Iron similar to your turbine housing (which can handle extreme heat, without much expansion or shrinkage). We've designed this common rail manifold with flow bench testing to increase turbo spool-up, and increase exhaust gas efficiency, all while maintaining exhaust gas velocity, so the turbo will function optimally. We've made the end ports flow more similar to the center ports so the end ports EGT's won't be extremely hotter than the center ports. Stock manifolds and one-piece competitor manifolds are known to shrink significantly, causing manifold-cracking, gasket problems, and exhaust flow problems created by exhaust port misalignment. Even stainless steel manifolds will shrink significantly, causing misalignment. The dirty little secret is that competitor's stainless steel actually moves (expands and contracts) more than ductile iron does. This DPS 3-Piece Manifold, on the other hand, allows manifold to expand and contract with heat, eliminating warping and cracking to the manifold, eliminating the dreaded manifold shrinkage. This is a great performance manifold for the larger T-4 Turbos. **Some modifications to engine and/or vehicle will be necessary, as the stock turbos are not T-4 flanges. **Will fit on the cylinder but does not put the turbo in the stock locations for truck years 2003 and after (fits the head ports of 1998.5-2018, but is NOT a stock replacement) A stock manifold flange is a T3 and this is a T4. **DPS Exhaust Manifolds have been granted an exemption by CARB, which means they are legal to be installed and used in the state of California, on vehicles 2007 and before.**