2006 Mercruiser 8.1

[Sea buzz]

Aluminum or cast iron exhaust manifolds?

 

[LG111]

By 2006 generally cast iron. Use a magnet if you get a chance to look. The aluminum has a smoother paint finish where the cast has more of a orange peal look. The aluminum also used water rails below the manifold hence two parts. Cast is one part no water rail.

Good Luck.