hey building a 318 got the pistons mixed up anyone know how to tell what way they go???????  

Do they have valve reliefs?, or do they have a notch on 1 side?
Typically factory puts the notch to the front of the motor[to keep them quite], which is what people generally want in a new car[ a quite motor].
You can run them with the notch to the back and free up 6-9 lbs of torque, this is something smokey yunick used to do and I've done a few times . It works.
If they have 2 reliefs ex/int, then make sure u have the reliefs in order,
[ exhaust reliefs on 1,7,2,8 are outward and 3,5,4,6 are inside towards/next to each other.  

Good advise.