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[JCEng]

I'd be very careful with this. Forged is NOT necessarily better than cast. A sophisticated geometry (e.g. strategically placed ribs and other shapes) can be cast allowing better management of stress and mass. While the forging process itself can produce better localized material properties, it's tougher to optimize the structural geometry and put the material where it does the most good. The result can be a heavier piston, and reultant larger loads on the rods & crank. These skyrocket at high engine speeds (roughly like crank speed squared). With mass being so critical here (as evidenced by the factory Ti rods), my bet is that the LS7 team looked at this very carefully and went with castings as the better overall choice. I don't know what alloy they selected, but there are some pretty decent castable alloys out there.

To be sure, forged pistons are often the right choice. I'm just not so sure here.

Remember, these engines have to make it through warranty and live. That's a lot harder than makiing it through the much shorter life of a race motor. If forged was right out of the box, they'd have done it as the cheaper bet than blowing motors.

Also, forged pistons are typically fit with larger cold clearances owing to their differing granular structure, but I doubt this would affect emissions. The sealing is done by the rings or you've got real problems.

Bottom line: Mods to this motor had better be carefully engineered or you're asking for trouble.