| 1. Measured at the widest area of port. 2. The ports on the SB Hurricane are purposely left smaller to allow a wide range of porting to match various head port configurations. However, the port runners themselves are much larger than the actual port opening. 3. Use this gasket on non-Magnum Engines. On Magnum engines use Mopar PErf. #P-4876049 4. Gaskets supplied with this manifold. 5. This manifold is 1.25" taller than stock manifold. | |  The ports on our manifolds are typically closer to the size of the gasket opening than most manifolds. This reduces the need for port matching the manifold ports to the gasket. Note: 53000/53001/53026/53036/53037 big block Chevy has oval ports, 52006/52007/52027/52028/52032/52033 Vortec has tapered ports. All others are rectangular | |