MerCruiser GM Big Block 7.4L/454 Cu-In 1984-2001 Exhaust Systems Products MANIFOLD ASY-EXHA #807078T10 Replaces: 807078T09, 807078A6, 807078A4, 807078A2, 89011A8 $543.99 OEM Mercruiser 807988A03 4 Inch Exhaust Riser (Hot Dipped) #807988A03 Replaces: 807988A2, 807914A1, 44354A3, 44354A13, 44354A10, 44354A9 $286.99 $334.99 PLATE-TURBULATOR #864838 $107.16 $117.50 PLATE & GASKET KT #8M0090726 $145.39 $159.42