big block questions

How thick is the stock steel shim headgasket on a 77-78 motor home 440? Im trying to squeeze the compression up a bit and was looking for thinner gaskets to go along with shaving the heads. And does anyone know the stock compression ratio, i come up with about 8:1 but want to double check that. And what was the factory horsepower rating? What i found says about 225 brake horsepower so thats about 250 crank right?