The Walbro 450LPH pump is the highest flowing intank fuel pump on the market, and is 100% E85 safe to boot. Walbro designed the pump to meet therequirements of modern turbocharged applications where a single 255LPH fuel pump is insufficient. The pump uses a turbine style design which incorporates two composite plastic blades, just like our HFP 255LPH pumps, as well as the Aeromotive 340LPH pump. 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 aftermarket exhaust setups. The Walbro 450LPH pump can flow anywhere from 15-120psi (Note! The bypass valve on the F90000274 pump opens at a higher PSI, making it ideal for LSX-based and other forced induction applications with base fuel pressure of 60psi or higher). 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 750rwhp (~800hp crank) on gasoline, and over 550rwhp (~650 crank) on E85. This pump can still support significantly more power than a Walbro 255LPH pump even when using stock fuel lines. We stock USA-made Phenix Industries universal bypass regulators for EFI applications with any fittings you need (-6AN, -8AN, etc). Give us a call or send us an email with any questions! 1-818-574-FUEL. Outperforms all current market in-tank fuel pumps Designed for engines with more than 500HP Award-winning OE Technology High-Pressure,High-flow performance OEM technology designed and developed for E85.