Mercruiser Replacement Exhaust

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MerCruiser Replacement Exhaust
Step Up To Replacement Semi-Tuned Cast Iron Exhaust Manifolds!

Don't replace your manifold with inefficient stock units. Get more power!

Independent dyno testing showed more power!

SEMI-TUNED MANIFOLDS

TYPICAL STOCK MANIFOLDS

Smooth radius at port exit directs exhaust gasses upward toward the elbow with reduced turbulence.

Extended porting within the manifold helps direct the exhaust toward the elbow which reduces back pressure and enhances flow.

Tuning allows for extended water cooling in the area under the port exit.

Exhaust gases slam into a flat floor causing turbulence and restricting flow, no direction given to exhaust.

Relies on a build-up of pressure to force exhaust to enter elbow.

These manifolds are direct replacements. Manifolds are sold individually.

Part No.	Description
390-5506	Direct Replacement for MerCruiser 454/502 Complete with all necessary plugs. Replaces MC# 89011A8 For use on GM 454 CID (.4L) and 502 CID (8.2L) engines.
390-5505	4.3L Direct Replacement Complete with all necessary plugs. MC# 99746A8 4.3L
390-5500	305-350 Direct Replacement Complete with all necessary plugs. MC# 87114A8 5.0L/5.7L GM 305/350 GM engines

MerCruiser Replacement Exhaust
Cast Iron Replacement Risers

This risers cast iron and fully water jacketed. It fits the standard MerCruiser style bolt pattern.

Part No.	Description
390-5706	Replacement Riser