You can purchase just the triple exhaust pipes or a
complete kit with
4 inch exhaust tips, flapper valves, hoses and clamps.  
Retain the  Benefits of THRU-THE-PROP Exhaust at low speeds!
The prop blades create a low pressure area at the hub.  
The low pressure area actually
PULLS the exhaust out of the
engine!  
This is very helpful for low speed torque and fuel economy.  
Thru-the-Prop exhaust should be retained on every MerCruiser for
best low speed performance and fuel economy!  
You can retain Thru-the-Prop exhaust with the Moore Performance
Triple Exhaust system!
TRIPLE EXHAUST
The Moore Performance triple exhaust gives the boater a true
Thru-the-Transom exhaust system at an economical price.

The triple pipe replaces the aluminum exhaust pipe and connects to
the Y-Pipe for Thru-the-Prop exhaust
and connects to an exhaust tip
installed into the transom for Thru-the-Transom exhaust.

Low speed performance/fuel economy is retained by utilizing the
prop-hubs low pressure area and high speed performance is
increased by eliminating high rpm exhaust back pressure.  

If you need the reduced back pressure of  Thru-the-Transom
exhaust for maximum horsepower but do not like the increased
noise level, installing muffler tips into the triple exhaust system (in
place of the straight exhaust tips) will reduce noise without
increasing back pressure.  With the Triple Exhaust, excess back
pressure simply flows through the prop (something mufflers installed
in a strictly Thru-the-Transom exhaust system can't provide).
Installing Triple Exhaust
Installing the triple exhaust is actually EASIER than installing Thru-the-Transom exhaust!  
With Thru-the-Transom exhaust the Y-Pipe needs to be removed and a block off plate
installed.  
This requires
REMOVING THE ENGINE!  
You do not have to remove the "Y" pipe with triple exhaust!!!
TRIPLE EXHAUST PIPES
# 575 300   $559.95
Triple Exhaust Kit with Exhaust Tips and Flappers
# 5753005                $175.95  two pipes