Where should the hole in the "single hole" ST 51 spray bar be pointed I'm thinking "down" in the same angle as the venturi? And what is a good needle setting to get started? I'm thinking 3 and half turns out?
I have been told that the location of the hole can be used to adjust amount of surge during the 4-2 break on a side mount configuration. Clockwise increases amount of surge for the insides and counter clockwise for the outsides. Just like the tank is used to regulate the engine speed level vs. inverted, so does the position of the hole regulate how hard the engine surges on insides vs. outsides.
I've always put the hole pointing directly down along the center-line of the venturi and have not had an opportunity to test above theory.