how much boost can i run with a built block but a stock ls head and about how much power. tuned with aem

 

Be more specific about the built block. You really don't need to do much to the head minus P&P. Depending on what kind of pistons you're running you could probably run between 10 & 15psi. But to be honest, if we don't know what you got in the engine there's no way to give you a good estimate.