I just finished a Boss 302 which is close to a 351C. The problem was smoking at idle, under power and
oil consumption. The 351C will draw
oil into the intake ports if the intake gasket is bad. This is what our problem turned out to be. This was a fresh motor but the gasket started leaking right away. If you think there is any blue smoke I would check the intake gasket. If the problem is carburation you shouldn't be using any
oil. The way rings seat now days you shouldn't ever have an oil consumption problem beyond normal, especially on a new engine.
Don