Keeping engine transmission tightly together will help in a street motor and is critical in any performance effort. This connection not only is critical to avoid havint the gasket blow out but combines the regidity of the gearbox to the engine. This performance bolt kit includes special 5/16 X 24 bolts with a unique head design to allow for use in small area. Note: the block must be retapped to accept these and the transmission must be drilled. Our kit also includes a hard to find 5/16, 12 point socket.