Just wondering what an experienced engine guy would think. I just tore down the 73 350 small block that was in my 71 chevelle. It had low compression on 1,3,5 and 7 (<100). All four of these pistons are cracked between the two compression rings and pieces fell out. Would low oil or overheating cause this? Does this have something to do with the direction of coolant or oil flow?? 2,4,6,8 pistons look fine and had good compression (>200). Any ideas for a rookie engine builder??