That’s true...we have no way of knowing what level of machining was done. I always hope that the machinist keeps up with current technology. It’s moving so fast right now (ring tech, oil tech and even piston skirt finish) that what was top of the mark 5 years ago is just passable today.
The other thing I forgot to mention is the high compression with no way to cool the inlet air is a recipe for serious detonation. The OP could be running into enough detonation it’s upsetting ring seal and that’s where the combustion pressure is coming from.
You know as well as I do how critical engine temp and inlet air temp is when running higher than orthodox compression ratios on pump gas.
The tune up window gets substantially smaller as the CR goes up. And what would be a small tuning error with a lower CR becomes a huge error with that CR and boost.
