The 123 Ignition System is a complete replacement distributor, incorporating a sophisticated solid state microprocessor housed within a polished aluminium body. The processor includes 16 selectable engine series specific ignition curves, including exclusive performance curves to suit Stage II and other performance engines. Simply select the ignition curve which matches your MGs engine number for perfect timing and smooth acceleration. Delivery of the timing through a micro processor provides superior accuracy, reliability and responsiveness over standard ignition systems. A proven and simple to install performance ignition system, 123s are now fitted to thousands of MGs. Available for all classic MG models from MGA onwards, offered for positive or negative earth, with or without vacuum advance, Side or Top Entry cap. User programmable, dual polarity 123s are also available allowing users to map their own ignition curves; making them ideally suited to MG owners looking to switch between road and track settings with the minimum of fuss! (Laptop required, minimum system requirements apply. Contact our sales team for more information). T/E (top entry), S/E (Side entry). Negative earth unless stated.