2.5" center to center. In the event of a backfire, TBS Pop-Off plate reduces the risk of damage to your blower and manifold, by allowing passage of the accessive pressure from the blower through the manifold's Pop-Off plate.
*Only works with TBS street intake manifolds. If another brand manifold is drilled for the Pop-Off plate with a 2.5" center to center, TBS Pop-Off Plate will be applicable. If Customer is willing to modify manifold for 2.5" center to center Pop-Off plate, Kit will be compatible.*