This 360 only has a MP 280/474 cam in it but runs pretty strong while idling about as smooth as stock. I don't know why it doesn't lope but I'm fine with it. A one legger would fry the tire for a city block if I dared to stay in it!
Then it might not be the 474/280. Did you put it in there? That's REAL close to the Hemi cam and the Hemi cam counted um off in the Hemi. It was a very noticeable idle. So you definitely should hear it in a 360.