This part is made to be a direct replacement for the factory front exhaust manifold on any 3800 series II or III engine, supercharged or non-supercharged in a front wheel drive vehicle.  Unlike the rear exhaust manifold, which is tubular from the factory, the stock front manifold is cast iron, and this casting is also much more restrictive than the rear manifold, which results in uneven flow between the cylinders on the back bank of the engine, and those on the front.  This new tubular design alleviates this problem by matching the size of the tubing on the front manifold to that of the rear.  Primary size is 1 5/8", and secondary is 2 1/4".  The header flange and crossover flange are precision laser cut out of 3/8" thick material for extra strength.  The donut for the sealing of the front exhaust manifold is CNC machined out of TT304 stainless steel, and then welded to the crossover flange, providing a perfectly made permanent sealing surface instead of a composite donut gasket that needs replaced every time you have it apart.  All materials of this exhaust manifold are made of high grade T304 stainless steel, unlike competing versions which are made in lower grades of stainless steel, which do not have as much corrosion resistance.

Look for horsepower gains of 10-15+ hp on completely stock vehicles.  More modded vehicles can see more.  If you intend on making in excess if 300whp, we recommend going with headers instead of exhaust manifolds, but for those looking for a good bang for your buck for a beginner mod, this is a great way to go.

This product is not designed to fit rear wheel drive 3800 powered vehicles.