Are you using the EGR circuit?
I haven't followed this thread closely, can you post the stock .bin you started with so I can find stuff? Most stuff I have seen can usually accept 5 more degrees of timing on a stock timing table if the engine is stock. If much has been changed you have to tune accordingly. Hopefully more experienced LT1 guys can chime in with how much is acceptable, shoot, they have a pretty aggressive timing table from the factory due to the reverse cooling so I creep up on it and do a lot of logging.