Can anyone identify what these pistons are? They were in the 914-6 engine we tore down last weekend. Best I can tell, the interior is cast / forged with:
S0V69
C031M
The google machine isn't turning up anything on that or variations that seem obvious.

I know, I should have taken a side shot. I got so focused on looking at the rings and trying to find a number that I forgot to take side photos.

Click to view attachment
Click to view attachment

Looks like a Mahle 80V69 which is 2.0L 911-T 68-69 80mm 8.6cr

Not original 1969 911 T or 1970 914 6 (same engine) based on the barrels only.
Our cars have cast iron (rusty) barrels. Yours look more like alloy...maybe Biral
The pistons are unfamiliar.
What's the diameter ?

Its the lightiing..cast iron

I agree cast iron barrels.
Stock pistons

I was able to get my dad to take a few photos. The cylinder ID is roughly 80mm.
Click to view attachment Click to view attachment

914-6