Edelbrock Exhaust Header Bolt Kit #8540 contains a set of 12 high-quality black oxide steel flanged bolts for universal applications that require a 3/8-16 thread pitch and 3/4-inch length. These header bolts feature a combination hex-Allen head that allows you to use a 7/16 combination wrench or the included Allen head socket. The flange design helps to distribute pressure and eliminates the need for separate washers. The black oxide finish provides a nice aesthetic look with mild resistance to corrosion in dry environments.