engine vibration 232 engine

["Jay" <jciampi@xxxxxxxx>]

Hey Guys, i have a 66 American with the 232/2bbl engine. I have set the 
timing, set the idle speed at 700 rpm in neutral/ 550 in drive. The engine 
has new plugs and points, doesn't appear to have any vacuum leaks.  At the 
550 rpm speed the engine has a rapid vibration which is quite annoying. The 
vibration mostly stops when i speed the engine up above the idle.  I have 
replaced the tranny mount which was dissolved from tranny fluid getting on 
it before i got the car. Could the engine mounts be so old and  stiff that 
they won't absorb even the slightest vibration and transmit it to the frame? 
I had a 65 American with a 232/2bbl when it was new in 65 and i don;t 
remember it being anything but smooth idling. The engine runs smoothly as 
far a vacuum gauge shows, no fluctuations due to worn valves or rings. The 
engine doesn't smoke and has 120k miles on the odometer.  Someone did put 
the oil kit from the side of the block up into the valve cover as suggested 
in a service bulletin. I know that has nothing to do with the idle. Just 
mentioning it as I hadn't seen this done to many 232 engines.  I didn;t 
mention it but the engine has new plug wires also.   Any ideas?

Jay in Central FL.