I have a friend of mine with a '69 Chevy Nova that is running a mildly built 355 ci small block. He was running 12.10 - 12.20 in the quarter mile. He put a ProCharger blow through set up on it with about 7-8 pounds of boost and now he runs 11.20's all day long. I would say that properly set up, it will really wake that 340 up.....