The manifold above is known as the "Center Riser" manifold. It
replaced the MerCruiser "LOG" manifold for the 1983 model
year.  The log style manifold has the riser at the back of the
The Moore Performance manifolds are an exact replacement for
the 1983 and newer 454 502 MerCruiser Big Block Chevy
manifolds.  The external dimensions are identical with all holes
drilled and tapped like the original manifolds.
Dimensions of Mercruiser manifold and riser
Cutaway view of Mercruiser manifold
Cast Iron   # 51240   $149.95
Mercruiser manifold to head gasket BB Chevy
Mercruiser riser gasket restricted style
Mercruiser hose fitting with drain plug
Each manifold includes a stainless steel manifold-to-head
gasket, a stainless steel manifold-to-riser gasket, installation
studs or bolts, and a 1-inch hose water inlet fitting.  
Mercruiser manifold, gaskets and bolts
Mercruiser riser open style
Manifold manufactured using Lost Foam process
Highest quality manifold machined to exact specs
Questions?  Call Dennis Moore @ 626-357-3573
Mercruiser Exhaust Manifolds
Chevrolet V8 454/7.4L  502/8.2L
1983-newer Replaces Mercruiser Part Number
807078A6 807078T08