I've noticed that Finnairs Md-11 engine vary slightly from the shorter stubby cones : http://www.airliners.net/open.file/1113223/L/
to the long cones:
to some that even have both :
this one is esp wierd as it has engine no1 and 2 the same but 3 is different
they are both the same manufacturer but why the difference in size of the exhaust cone?