Depending on camshaft and some other things,on 8lbs I'd start at 32-33 not pulling any and read the plug from there. I've seen some sb stroker stuff make more power with more(35+) and some with less (30-34). This being said, if the intercooler isn't efficient, maybe start a tad lower. Also, non projected plugs are a must.
Most people wait till 8-10psi on turbo cars to pull timing to aid with spooling as well.
