I don't know, Like I said,I know lot's a guys running forged pistons on the street with no unusual problems.I'm running forged Venolia pistons in my 302 project.Venolia themselves recomended .005 clearance on this 4.030 bore engine,they told me to expect no piston noise and ring seal that lasts as long as a cast piston in a performance street engine.
Many Chevy Big Blocks came with forged pistons from the factory,the current 454-425 hp crate motor has forged pistons and a 2 year guarantee.Mopars of past used forged pistons in the 440 6 Pak engine and Street Hemis
Currently,the new 7 liter Z06 Vette has forged pistons as did the LS6 version I believe.Many Japanese performance cars have forged pistons,notably the turbo supercharged models.
