CM 870 looking for more power

[CornHauler]

I have a CM870 CPL8519 with AB10339.17 that I am rebuilding to the higher hp CPL8518 which is basically adding the spring loaded idler and cam gears in the front from what I can see. But the question is how much power can I get out of this thing safely and what tune do I need to do it? It is out of a 2007 379 Pete with RTLO18913 and 3.90 gears pulling 154,000 gross most of the time. I don't really want to delete it I just want it to run right. I had the block machined and liner heights are at .013.