i have to say fair play for fooking a YB block like no one else ever has true performance.

looks to me like it may ( and this is obv only from a few pics) have simply pushed the bottom of the block away with sheer piston force on the ignition(power) stroke, many ways to prevent this if thats what happened, couldnt be so sure without seeing it

this is what happens to development engines, im sure it was expected at some point guys.