Hi Walter, no it has nothing to do with the piston. It's a machining process on the case. It aids in the blow-bi of the skirt to where the skirt fits on. Its the area where the oil squirters are installed. I have seen cases massage in that area for a better blow by exiting from the bottom of piston to cylinder wall. I know what it looks like, but its hard to explain, it has to do with milling/grinding the oil squirter area, I call that area the saddle to skirt rest ahhhhhhhh
. Sorry I don't know the proper nomenclature. There are three things left that I would like to have done on my case. 1. Have john Edwards shuffle pin my case. 2. Get that area around the squirters machined. 3. Have the case cyro treated.