since this was up I thought I'd add my .02, I just did a bottom end for a guy that did the window in a cast piston. When the piston let go, it wrecked the cases, rod, and cylinder. The tranny, clutch and head were only things salvagable. What's crazy is he wanted me to do the window for him again, fortunately I talked him out of it.
There is a moral to this story, and I hope it will open some eyes