well, I don't want to mess with it, that's why I posted. I guess I should have done a new thread.
The repacement piston is a lot lighter than the original, and it has thicker rings. It fits in my bore exactly like the old one. The diffrence is that on the old piston, the skirt on the intake side is about 1/8 of an inch shorter than on the new one. I recently got annother sachs motor, and it has a piston exactly like the repacement one I just got, but the motor has the tapered cooling fins and smaller ports than the square-fin one, which is what I'm going to use. The encourageing part is that there is a line drawn (very lightly with marker) on the replacement piston where I would need to cut.
If there was a place to research specifically, I would. Untill then If I screw it up, I at least know that it was me who screwed it up.