Inliners International Forums General Discussion Engines boring out a 250

I've seen standard cast aluminum pistons (low silicon, not hypereutectic) for the Chevrolet 250 by Sealed Power (Federal Mogul). Speed Pro(also Federal Mogul), does offer hypereutectic piston with content of silicon 16 - 18%. But I have not seen any offered for the 250. Do you have a model number? I would like to order a set if available.