Paraman, as a point of reference, I built an early 5.3, 2001 if memory serves me well, that used mildly ported LS6/243 heads, LS6 intake, headers, and a small cam similar to what hifi utilized in his build. The car put 350hp and 350tq to the rear wheels through a 5 speed. The torque curve was ridiculously flat and broad. The engine sounded great at idle and drove even better. Point being, these are great engines that perform really well with simple modifications. You're on the right track. Don't over complicate this and you'll have a great engine on your hands. Good luck!

Out of curiosity, how much material are we talking about having removed, assuming these are virgin heads that haven't been decked previously?