When dealing with a Heui Injection system not only is the oil pressure to the injectors highly important, but also the Fuel Pressure, Bostech has introduced their ISK641 which is the answer to this issue. With this kit you not only receive the spring and gaskets, you also receive a Billet Fuel Pressure Housing. This housing is an important part of this kit because over time the stock housing becomes very brittle and in some cases the threads become fatigued and strip off of the housing. The ISK641 is the most complete kit for increasing fuel pressure on the 98-03 Ford 7.3L Power Stroke. The ISK641 is designed to bring fuel pressures back in check to ensure longer service life of your injectors.