8.1L Aluminum Exhaust Manifold for Fuel Injected Indmar Marine Engines.  These manifolds are raw aluminum color and say Malibu on them.

GM Big Block Marine Engine Applications.

Mounting package for this manifold is 49-5141

Mounting package for Risers is 49-1004

Manifold to Head Gasket - CLICK HERE

Direct Replacement for Model Years:  2001 - 2011

Also Replaces Manifold Part Numbers:

53-1278 - 53-1279 - 31078 - 53-1021

Complete Exhaust Manifold Replacement will require the following parts:

(2) Exhaust Manifolds 53-1278 - This item.

(2) Risers 53-1077

An iron substitute would be the CHVA-1-84 (Barr) and 20-0100 (Barr) But the riser is shorter.