2 Mercruiser 330 340 Chevy 454 7.4 8.2 502 Exhaust Manifold big block 7.4L 8.2L

Description

TWO Exhaust Manifolds for Mercruiser Engines: 454/7.4L and  502/8.2L
Replaces Mercuiser 807078T10, 807078T09, 807078A6, 807078A4, 807078A2, and 89011A8
Replaces
CASTING NUMBER 866632-C
This manifold is an exact replacement for the stock manifolds. Left and Right are the same
These manifolds are the same externally as the factory Mercruiser manifolds but these have 30% internal cooling surface area to reduce exhaust temperatures.
Gaskets have tinged tinplate-reinforcement. These Manifold Gaskets are made from flexible graphite composite reinforced sheets laminated with stainless steel (marine grade) foils. These are NOT cheap paper gaskets!
See picture for independent test results.  These manifolds produced 12HP more over stock manifolds!
Fits 1981 and newer Mercruiser 7.4L and 5.2L engines up to engines with serial numbers that start with 8M.
Includes:
Two manifolds
Two block gaskets
Two riser gaskets
Two hose elbows