Center of thrust
The center of thrust or thrustvector is the direction in which the thrust is acting and on which point the thrust acts on the craft. The thrustvector and center of mass should be in one line to minimize steering.
Placing engines above the center of mass doesn't make a craft more stable, which is usually called pendulum rocket fallacy. In Kerbal Space Program such craft might be more unstable, as thrust vectoring needs to be applied inverted, when the engine is acting above the center of mass. So one way is to deactivate thrust vectoring, which makes rocket hard to steer especially in atmosphere. Another way would be to control in the other direction. To prevent the systems to counteract, torque of reaction wheels needs to be deactivated and all control surfaces needs to be removed.