Oil in coolant, engine sputtering

How do you knwo there's oil in the coolant? Are you seeing a slight sheen in the radiator? That is more than likely just the leftover stuff from the inside of the manifold passages. You are MUCH more likely to see water in the oil, in which case the oil turns cloudy and milky looking. Have you quadruple checked the firing order? Pay special attention to the "5-7" of 18436572. Was the Deman brand new? Have you checked the float levels? Ignore the part about not messing with the idle speed screw(s). You will have to to tune the car. What cam was installed? Timing should be more advanced than 8° for most setups. Before you start worrying, ALL carbs need some adjustment when installed. And most of the time it's just minor stuff.