Cummins Signature 600/CM570 build

I have an '03 Freightliner Classic with an ISX Cummins & it cracked down a headbolt hole. I couldn't reuse the block, so I'll be starting over from the ground up! Reuse the existing crank & rods, but everything else will be brand new. It would be nice to make some decent power as well. It was suggested to me to rebuild it marine/industrial spec or rebuild it using QSX pistons to lower the compression ratio to handle a power increase. I've seen a Cummins on YouTube that put down 876 on the dyno & I know a guy who put down 953 on the dyno. Does anyone have any ideas or suggestions to point me in the right direction? For the record...no, swapping a Cat isn't currently in my plans for my truck! I would like to put back what came out, but much stronger.