Upgrading my 340

I have rebuilt my engine through a machine shop that upgraded my heads to aluminum with much bigger ports. I wish I knew what the specs meant. The car dyno's at 320 HP to the wheels. I have a 650 double pumper on it. I'm thinking of buying a complete aftermarket 6pak setup. I think from Herbs Automotive for $2800.00

My question is : Would it be better to invest in a good electronic fuel injection system instead? What kind of increased power may result in differences between the two systems?