Performance Product Technologies Question & Answer Forum

Topic: Mercruiser Exhaust Systems

Question: Why can I not find a replacement “cast iron” exhaust manifold for my Mercruiser 3.7L 470 engine?

Response: Mercruiser did away with the cast iron manifolds due to ongoing quality issues with the manifolds cracking. Therefore the Aluminum is the only option offered today. If you have the aluminum design you can go with just the 816219A 5 replacement manifold, however if you are replacing the cast iron manifold you will need to order the 816219A 4 kit which includes the manifold and riser. You can select the second link below and enter your serial number to find the gaskets you need as well. The system will give you the estimated shipping cost as well. Let us know if you need any assistance we will be glad to assist!

Exhaust Manifold – OEM Options (link to product)

Exhaust Manifold – Direct Replacement Option (link to product)

Part Diagram – 816219A 4 (Manifold and Riser) (link to part diagram)

Part Diagram – 816219A 5 (Manifold Only) (link to part diagram)

The images below show the exhaust riser height configuration and height relationship with the AL exhaust system.

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