The material is made from iv been told is toughened steel. It was tuned and running fine at 290 rwkw for the last 2000 kms motors done 26000. D&T done the tuning last, 2 months ago, I was heading up there that morning to get the tune on it when it went. The bores were like new no scoring. Top of piston was left in the top of bore and the rest was in the sump in small bits. Pistons were all fine not running lean no detonation 1 bent valve.