you must drop the compression if running a carb on this setup. Get some gigantic injectors and build it well and it should be okay on 9:1. Intercooler, water/meth inj, timing, and tuning tuning tuning. The carb I don't think will get you there without a few surprises.
... my question is why aren't you just buying an lsx so you don't have any doubts or headaches or waste 10,000$. Seems like you have the money to me.