Pishta, if I'm understanding correctly the dimension across the intake manifold valley, between the two head lands, I measured as 6.848". So considerable milling, consistent with the work done on the manifold? Seems like way too much.
The rod length is a little harder to estimate with the piston still assembled. I used a straight edge to extend the rod mating surface parallel to the wrist pin and measured to my eyeballed center of the wrist pin and got a measure of ~6.075" The rod mating surface is serrated, so I assume the actual measuring surface would be at half the tooth depth. Unfortunately, the BME receipt I have doesn't have any part no. details.
I have the original receipts from Brooks Racing Components (BRC) which calls out the piston as 10-1-55-251. Google says that the current shop RaceTec (in Huntington Beach) is the second generation of BRC so I thought maybe they could decode the number and give me some piston dimensions. They're pretty close to you, do you know anybody there?