Edelbrock 2121 Intake Manifold
The Edelbrock Intake Manifold made of aluminum with a natural finish.  The rocker arm nut thread size is 7/16-20.   The manifold includes intake valves, exhaust valve, valve springs, retainers, locks, guide plate and valve stem seals, but does not include damper spring, rocker arms, nuts and drilled steam holes.  The guide plate pushrod size is 5/16.