GM Perfomance 19434412 LSX376-B15 LSX Crate Engine - 473HPLSX376 B15 Crate Engine 473HP Crate Engine 376 Cubic Inch 473 HP GM LS Series FORGED INTERNALS SUPPORT MORE BOOST! For builders who want to stretch the performance of a turbocharged or supercharged combination, Chevrolet Performances LSX376 B15 is the foundation they need! Its durable, all forged rotating assembly supports up to 15 pounds of boost. Our ratings of 473 hp and 444 lb. ft. are only an indication fo what the engine is capable of.