According to my how to rebuild a small block book, the 0 starting the casting number means 1980, The motorhome was a 1979-80, It was sitting right next to the motor when I picked it up Saturday. He took it out to put a 440 in it, to pull his Race car, and he said it was allway's a 4 barrel motor,and he bought the camper brand new. He put the Holley street Dominator, and holley 4 barrel on the motor in the 80's . I was just wondering what the HP designation ment, I doubt it's an E58 motor, like the little red express, but I'm assuming it has a little better performance then the standard 360 smogger of that year. Just to note, the camper has just a tick over 50,000 original miles on it.