Edelbrock LD340 WTH?!?!?

The LD340 is a great manifold especially for the street car. I don't think that the difference between high or low runners was done for performance reasons. The first intake that I ever bought was an LD-4B (1975). It was the 273/318 version of the manifold (I think first produced in 1964) and it has the runners in the other configuration.. It is also a great manifold. When I went to reinstall the AC compressor on my 1970 318 after the manifold swap, it wouldn't fit because the front runner that was high, was in the way. An LD340 (first produced in 1968) with the high runner on the other side works fine with factory air. I always made the assumption that this was the reason for the change.