Shark

I've noticed the engine in my '55 idles somewhat rough when in gear...not terrible, but noticeable, and definitely not as smooth as I would expect from a Mercedes V8. Out of gear (Neutral or Park) the idle is very smooth. Doesn't matter whether the trans is in C, S, or M. I've noticed it from the day the car was new, and since I'm bringing the car in for the free 1000 mile diagnostic check, I was going to ask the dealer to look at it. On the other hand, if this is normal for this engine, I don't want them trying to fix something that's not wrong. Anyone else have the same complaint? Have you asked your dealer to fix it, and what has the result been? Thanks in advance.