i was talking to the old bloke who ran thi motor museum in wikltshire and he said to me make sure your is ignition slightly retarded, becase we are running unleaded, sumut to do with octane level i think he said.
I think you just have to set timing to what your car wants, like David (126cab) used his timing gun to set mine to factory specs, but because my carb is dodgy it ran quite rough, so its probbaly best to find what your car likes by the method uve set it with.
Chris