I'm sure dp isn't going to be the greatest but cylinder pressure can lift the head easily. More timming more cylinder pressure and more stress on keeping things together/bolted down. I belive the water/meth will increase timming as well when being used so combine that with alot of timming in the tune can make cylinder pressures very high for the hp level your at. Not saying thats what caused it but would be something to consider watching when put back together so it dosen't do it again or bend a rod. I'm just speculating nothing more.