modru2004 why don't you go find out and tell us what the difference is. Seems that the same upgrades they did to get a 5.0 to a 5.0 HO they did to the 5.8, except I am not sure on the cam. Can't you just look on the upper intake manifold and it says 5.8 H.O. !!! as far as I know all came like that. But I don't know because I run a straight six............ with a 351w L.O. waiting to go in from the garage.