Finally, above water exhaust relief only when you need it, on the top end. Operates off speedometer system pressure. Easily disabled for totally quiet operation.

"Adds that needed extra horsepower, especially on modified engines!"

Exhaust By-Pass Valve Kit - Provides above water exhaust system pressure relief during high speed operation. Our automatic exhaust by-pass dumps your engine's exhaust before the lower unit, but only when you are above about 50 mph! Its stainless steel, hydraulic piston tee's into your existing speedometer tube to provide MPH controlled actuation. This means you can cruise around all day, pulling skiers and sightseeing without rattling the local environmentalists out of their sailboats and canoes. But, when you really want to go, it opens up to give you unrestricted top end (easily disabled for total quiet operation)! 
Note: it improves the stability of the speedometers needle too!

Order Part #117-001 for 20" OMC V8's only (Bolt in place of the production 20" OMC v8's fake exhaust outlet plate.)

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