Silvolite actually has a 410 piston, but it's cleverly disguised as a 390 slug with a 1.66" compression height:
http://kb-silvolite.com/spistons.php?action=details&S_id=157
The "trick" 390 piece would be the 1131, listed as 10:1, which is a true flat top with no dish. The 1130 has a slight dish at 9.5, and I think it matches up to the 390 Clevite I mentioned earlier I have here.
Also, their 352 piston looks a lot like the Clevite 352 I have, so I guess I have two sets of Silvolites already on hand.
The interesting one is the 1138, which is the replacement 428CJ piston at 10.3:1!!
There may be hope yet.
