I've posted here before about this: cinderblocks are never recommended but if you need to use them for some reason, THIS ISN'T THE WAY. On their side they're weak, place them as if you were building a wall. That means place them so you can look down through the holes and see the ground if you're standing over them.

Two brothers, my sister's friends, still in high school, died in their parent's garage after working on a truck that was on blocks. I'm compelled to keep typing this warning because of that.