Thread: Black Smoke

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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.

it's running rich, but the blower is probably toying with that carb. the timing is whatever you have it set at, being a blower motor, it could quite possibly be retarded, or set at the Chevy SBC base timing ( not shure what that is ). you probably need to ajust jets and metering rods in the carb, but the carb is what is doing it to you. or advance the timing a little and run higher octane than you are, and try that.

WE had a lot of trouble with those demons on a blower set up, redid the blower seals still ran rich and leaned out, ran out of ideas with the demons, and finally put a pair of Holleys on it, guess what ?, no more problems. TH ething that gets me is taht those demons were set up for a blower and the holleys were just a naturally aspirated setup, just a pair of Holley 1850 list 600's. See if you can beg or borrow a friends Holley 750 vacume secondary and see how she runs then.