every engine has a "lean" cylinder, depending on the intake manifold design. When highly boosted, if something goes horribly wrong with fueling, the lean cylinder can melt. I killed three Skyline engines, and the first blew only the 6th cylinder, which is the "lean" one with that manifold design. But I'm guessing against that, as IIRC I didn't lose 100% compression, and catastrophic preignition tends to take out multiple cylinders.