An ignition plug having a center electrode tip and a substantially aerodynamically shaped ground electrode mounted coaxial to the center electrode tip. This construction substantially eliminates shielding and increases the ignition presentation and the aerodynamic flow of fuel in the gap and tip area. This provides greater power, increased gas mileage and reduced pollution. A circular ignition presentation is achieved by positioning the ground electrode around the center electrode forming a substantially uniform gap. Sparks will be emitted from the ground electrode to the center electrode throughout the gap. This provides a greater region of ignition thereby igniting more fuel. Conductive coatings are applied selectively to the inner surface of the ground electrode to control the distribution of electron flow about the gap to improve ignition uniformity. The electrode and insulator in the plug tip have decreased abrupt surface contour discontinuities to allow for aerodynamic flow of fuel. The gap is set permanently at the time of manufacture thereby eliminating problems with setting and maintaining the gap. The ground electrode is formed as an assembly having a base and the plug base includes a recess adapted to accept the base at various positions. Used with a cone-shaped center electrode, the gap can be adjusted by changing the position of the base in the recess prior to affixing the base in the recess.