LS7 has 11:1 compression. You will need to do all the steps to avoid detonation. Without fuel injection, the leanest cylinder will be one of the limiting factors. Then you can't be sure of the quality of the gas at the pump, so you'll have to lower the ratio to account for that unless the octane booster really works. Last of all, do you have enough $$$ to cover parts replacement expenses if things don't go the way you expected, IE detonation hammers the rod bearing, melts piston tops, etc.
Look for small aluminum specs on the porcelin of the spark plugs, that tells you pistons are melting.
Airflow is very important for making torque and power, maybe give up a little compression and really go for airflow...from air cleaner to end of tailpipe.
