360 shakes

It should "shake the same" in or out of gear. Put it in neutral and slowly bring up RPMs looking for vibration. Do this with the engine fairly cool, so that you can pull the fan belts off and run the engine for a minute

Shaking in gear and not in neutral at the same RPM indicates

motor mounts transmitting vibration, IE metal on metal, or other metal on metal contact, engine to frame, headers to steering column, etc

Also a miss. Bad cylinder, bad plug, plug wire, etc. or even carb way too lean on idle mixture