Here is a problem I encountered on my first engine build at only 824whp. The engine was 11:1. I also saw the exact same issue on my Mazworx engine when it was being gone through. That engine is 10:1. I went from a .82AR exhaust housing to a 1.06AR exhaust housing and moved my peak TQ up 700rpms to 5800. These pistons and rods have been sitting in that box for a couple of years. It was distinctive when we first pulled the first engine apart.