273, could it be a commando and CAM question?

Yeah the dome tops have only 2 valve releifs and can be installed only one way.
The standard pistons have 4 valve reliefs and a notch to indicate which way the should be turned. This is because thr wrist pin is just slightly off centered. I was told one could install those flat top pistons backward and get just a tiny bit more compression from them but I haven't seen it or tried it.