That’s exactly what was done. I’m betting those pistons are .060 out of the bore. I have read about that I the NHRA stock rules. Not the same class, but you can run the piston out of the hole that far and still be legal compression wise for a 10.5:1 stocker. I would suspect they milled the decks a bunch and then did some milling of the heads and to get the manifold to fit that had to add to the flange. Very cool as I’ve never seen that before.
