Take a look at Jaguar XKE's and others, they are very simple carbs! you have essentially ONE variable and that's the needle. You can modify them or even make new ones if you have a laythe they were used in EVERYTHING from the Aston Martins to the Rolls Royce's AND are known for getting great milage. HP, I think has a book all about SU's.
True, Webers are the untimate but they also have about 40 variables each!, and the mysterious EMULSHION TUBES that follow no logical pattern.
Su's come in various sizes and (3) 1-3/4"s ill be great for your car
cheers;
Roar