Mr. Gasket Super Intake Manifold Bolts have a smaller-than-standard hex head with a special under-head radius for added strength and a wide washer-faced head that spreads the clamping force evenly. Designed specifically for small-block Fords, these durable 2.00-inch-long 5/16-18 bolts come with extra-thick heat-treated flat washers that deliver a more uniform torque and prevent galling on aluminum intake manifolds. Theyre heat-treated to Grade 5 specs, a perfect fit for tight spaces, have a protective black-oxide finish, and come in a set of 12.