horsepower question

does anyone know how much h/p an lt1 has? what about the lt1's that have the 54cc heads? what is the difference between the normal lt1 and the 54cc headed lt1 besides the heads? did these motors come in certain cars or what?

some sources said 285 some said 300 ill guess its something in between, but lt1 with 54cc stock?? I only know the lt4 came with 54cc heads