Nothing new there. I had a .030 (360) 408 combo with Diamond pistons that on its third rebuild the bores were so bad I wore out two sets of stones somewhat cleaning it up then hit it with my dingle berry hone. I saw some of the strangest marks in those bores Iv’e ever seen. That engine ran 9.73@135mph at 2880 pounds in my Duster and 10.10@3200 pounds in my sons car.
The only difference here is that these are cast pistons, should be around .001. No more than .002 max. What happens is the skirts collapse. Run a mic down the skirt if it doesn't keep getting wider, the skirts are collapsed. If it keeps getting smaller, a cracked skirt is in its future.These pistons have the oil supplied to the rings through a large window behind the oil ring. The silvolite line is a stock replacement piston like 80 bucks for a complete set.
