Thanks Pete. The GT6 is with my friendly professional mechanic, Tony, who owned and rebuilt an early Vitesse over many years. Unfortunately he has no experience of the later emission control carbs so I am trying to find answers and source parts for him to fit. My previous hands-on experience with classics has largely been with MG's from 1932 to 1980, I am now getting too old to do my own spannering so rely on Tony.