BBK Adjustable Fuel Pressure Regulator for GM TPI 305/350 are a great way to tune the vehicle to obtain optimum air / fuel ratios and achieve maximum horsepower. Each fuel pressure regulator is made from high quality CNC machined billet aluminum with a long lasting anodized blue finish. Each fuel pressure regulator is hand assembled with a precision leak free diaphragm that will allow fuel pressure adjustment to approximately 65 PSI. These BBK fuel pressure regulators are direct replacements for the stock pre set regulator and offer the best performance and value.