GM Small Block Center Rise Exhaust Manifold | Barr Marine CHV-1-83 Generic center rise manifold for GM 283, 305, 307, 327, & 350 cu. in. marine engines. Barr GM small block exhaust manifold Generic center rise manifold for GM V8 small block engine applications Interchangeable between port and starboard side Requires use of Barr 20-0100 or 20-0082 riser with this manifold Includes with gaskets and mounting hardware 3/4 in. NPT cooling hose connections Heavy duty cast iron Painted black Replaces Indmar 531051 Replaces Marine Power 0994-000 and 613287