Duramax 4" exhaust now available


$575 for the complete system!!

Hear the Kennedy Duramax 4" exhaust - Warning this is a large file (19.5MB)

Hear the Kennedy Duramax 4" exhaust - this is a small file (1.3MB)

Duramax Exhaust Install Schematic (pdf)


4inch head pipe Head pipe support rod

I start at the downpipe (Vee clamp flange)
and immediately upsize to 4".

The first support (alongside trans) is pre welded
to the first (often referred to as downpipe) pipe.

crossmember offset

hanger clamp

The offset pipe drops down, and hugs the drive shaft support bearing crossmember very closely. It then returns to the same plane to keep the muffler up high. VERY little of this system can be seen from side outside the vehicle.
The hangers are attached with HD muffler clamps allowing easy positioning and adjustability. System height can be adjusted, if necessary by bending the factory hangers either up or down and positioning the clamps accordingly.

muffler rear hanger-side view

Muffler louvers-smooth position

The muffler is a straight through design with minimal louvering internally. This has proven to be substantially quieter than the perforated core muffler (still available) while performing equally as well. The muffler rear hanger is designed to clamp on immediately behind the mufler. This allows room to install the stainless steel band clamps used to seal the joints. These clamps will not distort the pipes (allowing easy disassembly if necessary), while providing a perfect seal.

Spare tire clearance 5 inch

5 inch tailpipe end view

The tail pipe (shown in optional 5" dia) routes with plenty of clearance for the factory spare, and even allows for use of a larger size spare. It is supported again by a clamp on hanger. This same clamp secures the tailpipe joint (where applicable) while hanging the system at the same time. The exit is changed to approximately a 95 angle to the body line vs the OE 135 angle. I feel this looks better, and pushes the exhaust away from the fender line better. There is plenty of extra pipe here so it can be trimmed back if desired.


Duramax Exhaust Install Schematic (pdf)



For more information E-mail: john@kennedydiesel.com


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