Just an update. We pulled the 350 engine out of the Argosy this evening. Came out very easily. The previous owner had just installed the motor and the front end of the motorhome was still removed which made the job a lot easier. I bought one of those engine lift plates that bolt to the intake manifold in place of the carburetor. Worked very well.
To pull the engine I removed the starter, unbolted the engine from the transmission and supported the transmission. I left the heads, intake manifold, power steering pump, exhaust manifolds, alternator, fuel pump and dipstick in place on the engine and they posed no real problems during the removal process. I'm sure I won't be able to do that when putting the 454 in.
I know it will fit because the motorhome originally came with one
. Even so I might have to lift the front of the motorhome up a little more to make the angles work.
Brad