An adjustable fuel pressure regulator is an easy way to fine tune your air/fuel mixture at wide open throttle and help tune you fuel trim levels. The 85-92 TPI cars use a removable hat under the plenum that is replaced with our adjustable billet hat with six Torx screws. The kit even comes with the Torx tool and a fresh pair of plenum gaskets to top off the installation. This product is for fine tuning only. Not intended to make major changes to your mixture due to large injectors, rich idle conditions, etc...where programming may be needed