Another question which I can't get my head around. My car as a late TR4 [July 1964] is displaying strange combustion. Twin CD175 Strombergs are fitted. Numbers 1 & 4 spark plugs look as if the mixture is leanish, whereas numbers 2 & 3 look as if the mixture is too rich! How can the front carb create lead cylinder lean and trailing [#2] cylinder rich, and the rear carb create lead [#3 cylinder] rich and trailing [#4] cylinder lean? To my amateurish eye, it just doesn't make sense!
Best wishes Willie