Poly 318 Intake Manifold Heat Shield Removal
Factory cast iron A-block intake manifolds feature a sheet metal heat shield that collects grime (Figure 1). When using a factory intake manifold, it is wise to remove the heat shield since it is not necessary and provides limited benefit of keeping hot oil off the intake floor but poses a risk of collecting grime that could fall onto the camshaft lobes and lifter faces.
The heat shield is fastened to the intake manifold using spiral rivets. To remove them, hit the head with a cold chisel to lift it. Knock in a flat bar and pry out the rivets (Figure 2).