They aren't special per se, but they are different, judging by what I found when I tore the donor engine down. The pistons are dished, pretty much the same as all others, but the pistons and rods are full floating type, with retaining rings in the pistons to retain the piston pin, they are not pressed in the rod. The thrust sides of the s/c pistons appear wider or flared out ostensibly to provide greater load area and the rods do appear to be a bit beefier. This was a 1995 engine which was the last year of the Series 1 s/c, so I do not know if earlier years are the same or not. I have a photo somewhere.