Can anyone tell me who invented the E-Rock, today it is known as the the B-Rock.  Also what city was it needed for?

I don't know.

It seemed like a good idea to me to move the mass of the valve further away from the cylinder openings so as to facilitate the loading of rocky material into the cylinders. More continuous/smoother delivery and less boom bounce.

The E-Rock was drawn up by a pumper by the name of Gary Nichols, it was presented to Fredrick Schwing in Germany and two proto types where made - one of which is still at Nichols today.  The rest of the story goes some thing like this, brand P was out pumping the S brand in the Knoxville area so Nichols needed help and the E-rock or Extended rock was born. As we know this became the Big Rock and is Schwings best valve to date.

I think it could have been the G-rock or perhaps the N-rock.

Now we know the rest of the story.