I have been working on the engine dyno all week. Carter Performance here in Lake Havasu built three of these matching 557ci Big Block Chevys for a 42' Fountain. We provided three FAST XFI engine packages including Edelbrock EFI Intake, FAST Fuel Rails, FAST Dominator Throttle Bodies, FAST Dual Sync distributor, EFI Harnesses, FAST 65# Injectors, FAST/Aeromotive fuel pumps and FAST XFI ECU. All Three Engines were within 5hp and 4FT/LBS of Torque of each other. We netted a Peak HP of 668hp and 661ft/lb torque at 4800 Rpms. A Perfect Engine Combo For A Boat!!