Hi, today I removed the head of my 4e for maintenance. Anyway I have a question concerning pistons mark. OK on cylinders and pistons number 1 and 4, its written "2" and on cylinders and pistons number 2 and 3, its written. "1" Does this mean that the block is not stock? If I want to put New oem pistons, I must buy 2 pistons mark 1 et 2 pistons mark 2? I M a bit confuse about this. Can someone explain me how it works, thanks