318 hp question

For the long run, you may want to consider putting 340/360 heads on it for the better flow and bigger valves. However, you will lower the compression about 1.2 points. To compensate for the loss, the best way to go is to get 10.5 pistons, and with the larger combustion chambers in the 340/360 heads, you will end up at 9.2 compression - perfect for the street.