I currently have a stock 5.3 with 862 heads. I have a pair of 706's and a pair of 317's available to me. my question is, which set would be better for my build? whichever i go with I plan to have ported and valve job done. I will be running a nitrous setup for awhile, until I finish gathering parts for my turbo setup. I know the 706's are smaller chambers, and would probably work better on the nitrous combo, but the 317's have larger intake valves and chambers and will probably flow better with boost. or should I just stick with the stock heads and build the 317's until it's time to boost it?