I have a 23 t-bucket with a chevy 350 in it. the motor has been completely rebuilt, balanced and blueprinted. I have a B&M street blower, and the motor was built for it. I have a Demon 750 carb on it. ????, Does anyone know what the timing is. it runs pretty good but when i lay into it i gey alot of black smoke out of the pipes and the plugs are turning black aswell. It acts like it is running rich, but when i lean it out it runs bad. Anyone have any ideas.