Because of the runner width and cross section, rotating the carb 90° will place the throttle bore that is toward the engine side almost 2" closer to the head, making it more suceptable to being over rich and almost hidden entirely inside the center runner shrouding the 2 end runners from its contribution to the rest of the engine. The carb placement with the throttle bores being parallel to the head is the same design that is used on similar OEM 2 BBL intakes from South America Chevy 250's, so its really not an unorthodox design as it might be considered.
