The business was established by an American businessman, James F. Conway and William K Curtis in Tralee, Co. Kerry, but was moved to Castleblayney, Co. Monaghan, before production began. The aim was to produce a large luxury car model for export to the US market.
Shortly after production began, however, design flaws became apparent. Although the car was big and heavy, it used a relatively small Austin A55 1.5 litre engine, which limited performance. The A55 also provided the transmission and suspension. Another problem was that the rear wheels were shrouded by body panels and a rear wheel could not be removed (for puncture repair for example) without dropping its axle. The car used fibreglass body panels and was styled as a four seat, two door, coupé with removable hardtop. The wheelbase was 98 inches (2487 mm). All cars were painted white although one in the USA has been repainted candy green
Production of up to 10,000 cars a year was talked about but as few as ten complete cars were produced during the six months before production ceased. After the factory closed, the unused parts were dumped into the local lake, Lough Muckno.
The car is now very rare, and only eight are believed to be still in existence: five in Ireland — one each in Killarney, Castleblayney, and Wexford and two in Drogheda — and three in the USA, one in (Seattle) and two in (California).
- "Shamrock Car Returns Home For Festival". castleblayney.ie. 2006-07-07. Retrieved 2010-04-11.
- Jonathan A. Stein (2005-03-21). "1960 Shamrock: The Luck of the Irish". AutoWeek. Retrieved 2015-03-17.
- "Shamrock Car on Irish Classic car forum Boards.ie thread".