Mallory Manifold Riser Kit for 454 V8 Mercruiser. Kit includes:
2 Manifolds 9-40506
2 Risers 9-40559
2 Manifold gasket and bolt kit 9-40575
2 Riser gasket and bolt kit 9-40578
This is the full kit and includes all of the above listed items for 4 inch riser setup.