It is running terrible but I had assumed it was a tuning issue because I have to get the superchip fine tuned on the dyno. It backfires on acceleration. Compression values are within 15 % across the cylinders. The leak is coming out at the very rear of the head between the cylinder head and the block. So what is my fix ?

I assume pull all the ARP head studs and re-seal the threads and new head gaskets ? I didn't build the engine so I don't know if the head studs were sealed