I Want To Beef Up My 340 Motor (help Please)

Hi All,
I wanting to pull the engine out of my car this winter and have it rebuilt. The car is a 1969 Dart 340 Swinger. The motor and transmission are numbers matching to the car. The previous owner rebuilt the motor and it was not a professional job. What I am wanting to know is what would be the best street set up for this motor. I had the transmission rebuilt (727) and have a kit put in it. I just got a fresh rebuilt Dana power Lock with 3.23 gears. I just feel that need for more speed and power. Do not get me wrong the car gets up and go’s now, but I feel that the motor has more to give. I would appreciate any suggestions.

Thanks
Joe