Need help Identifying 340 pistons

Garrett Ellison said

Looks like a sealed power 428P cast piston. I haven’t been able to find the piston head volume for those yet.

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Me either. I just "went with" some real similar 4 eyebrow pistons and used 12 cc's. Using that, the .010" outta the hole and the FelPro blue gasket at .039" I got 9.4:1. That's probably real close.