Way too much runner volume for a mild engine IMO... Takes a lot of engine to need a 210 runner, a mild engine like yours would have done much better with something in the 180 range.... By the way, what is this engine in, what transmission, what rear end gears??? Also, during the rebuild was the engine deck height set, balanced or just bolted together??? Without knowing compression ratio on the engine, and many other details anything for improvement would be just a guess.....