Quite simply the best ported manifolds you can get for your 3800, these are perfect for those looking for the maximum performance for the buck. Our ported exhaust manifolds will reduce backpressure, reduce knock, and increase the width of your smile every time you hit the gas. We strongly recommend a 3 Inch downpipe for best results.

 

So what makes our ported & polished manifolds so good?

• We port and polish our manifolds. See the "Tech Notes" section below on why this is important.
  
• We weld extra material on the outside of both manifolds to allow for maximum porting (See "Tech Notes")
  
• We remove the EGR pipe intrusion
• We clean up the 02 sensor bung
• We don't just blindly port... Bigger is not better; It's important to retain a "D" shape on the front manifold.

Here you can compare a stock front manifold primary to our modified primary. As you can see, the stock piece has more of a rectangular opening whereas ours is opened to take advantage of the entire opening. As well this area is polished to increase flow.

 

We can open the fronts up further than ever before by welding extra material onto the manifolds as seen here. This area also gets quite thin when any kind of porting is done. The extra material eliminates the chances of a hairline fracture as some have seen on other manifolds.

 

 

 

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Porting versus porting and polishing - So you might be wondering what advantage there is to our polishing the manifolds as well as porting them. Think of your engine as a large air pump. The more air you can get in, and consequently out, the more power you make. Velocity and exhaust scavenging play two very important roles in the play. A smoother (polished), smaller tube will flow more than a larger unpolished tube. Porting a stock manifold does little good if the surface is so bumpy that it creates a turbulent layer.

What's a turbulent layer? When there are ridges, bumps, or other imperfections in the tubing, the tubings "effective" size is reduced as the air loses velocity around these imperfections. Every manifold or header will have some degree of this phenominon, but the quality determines how much. If a ported manifold is carelessly made, it can actually flow worse than a stock manifold.

Welding of extra material - Why do we weld on the outside of the manifolds? Well, this is two-fold. The rear manifold is tubular steel connected to a flange with a weld on the inside diameter. To open up these ports we remove this weld and attach the tubes to the flange via a weld along the outside diameter. This allows us to open up the rear manifold significantly.

The front manifold is a cast unit and differs greatly in design from the rear manifold. Most just open this up as far as possible and do not weld it. We take this one step further by adding extra material to the front manifold (we beleive we are the only company to do this) which allows us to open it up significantly more than normal.

 

Your competition claims to "add the most weld of any 3800 vendor". - This statement is so silly it shouldn't require a response but the amount of weld has absolutely no affect on manifold performance. Adding extra weld doesn't magically make a manifold perform better.

 

• 1997-Current Grand Prix w/ 3800 Series II or Series III engine
• 2000-Current Impala w/ 3800 Series II engine
• 2000-Current Monte Carlo w/ 3800 Series II engine
• 1997-2004 Regal w/ 3800 Series II engine
• 1995-Current other FWD vehicles w/ 3800 Series II or Series III engine
• 1996-2005 Bonneville w/ 3800 Series II engine

Please Note: $50.00 Core Charge is applied to purchase and is refunded upon receipt of your stock exhaust manifolds. Cores can be sent to the address below. Please note, this address is just for exhaust manifold cores.

W Body Store - Core Return

827 North Chestnut Avenue

Arlington Heights, IL 60004