All new for 2011, the Walbro F90000274 450LPH pump is the highest flowing intank fuel pump on the market, and is E85 safe to boot. Walbro designed the pump to meet the requirements of modern turbocharged applications where a single 255LPH fuel pump is insufficient. The pump has an innovative design featuring a single impleller with two parallel rows of turbine blades. The turbine design lends itself to extremely quiet operation, especially compared to Walbro's previous "gerator" pump design that had metal gears which were notorious for a very loud whining noise which could easily be heard over even the loudest aftermarket exhaust setups. The Walbro 450LPH pump can flow anywhere from 15-120psi (the bypass valve is set higher than Walbro's previous fuel pumps, which were around 85psi). Final fuel pressure is determined by your fuel pressure regulator. Please note that this is an aftermarket fuel pump, and some modifications may be required to get it to fit. The overall size is very similar to Walbro's previous generation GSS340/GSS341/GSS342, however the base is slightly enlarged as shown in the pictures. Horsepower capabilities? No other intank pump on the market can come close. This pump can support over 800hp using larger than stock fuel lines. This pump can still support significantly more power than a Walbro 255LPH pump even when using stock fuel lines. The F90000274 requires modifications to system wiring, fuel lines and the fuel module, and should be professionally installed. The blades feed two high-pressure pumping channels, as opposed to conventional single-stage pump that uses an impeller with a single row of blades at its outer edge. This innovative design results in improved hot fuel flow, as well as minimal noise and current use, resulting in efficiency that's 20 percent higher than conventional pumps.