my lil 6.1 died at the 1000ft mark at the track

not possible that a bolt can lenghten? I think ist more likely it broke lose for some reason. But it scares me a bit for the replacing engine. this broken one is a 2010 engine... will be replaced now by a 2008 6.1 out of a C300. Are there differences? Pistons, rods, oilpump...